AI-901 — Microsoft Azure AI Fundamentals Quick Reference

Compact AI-901 quick reference for Microsoft Azure AI workloads, Azure AI services, machine learning, vision, language, speech, search, and generative AI.

How to Use This Quick Reference

This independent Quick Reference is for candidates preparing for the real Microsoft Azure AI Fundamentals (AI-901) exam from Microsoft. Use it to connect scenario keywords to the right AI concept, Azure service, workload type, or responsible AI concern.

Focus on these recurring exam decisions:

  • Prebuilt AI service vs custom machine learning
  • Classification vs regression vs clustering
  • Computer vision vs OCR vs document intelligence
  • Language vs speech vs translation
  • Search index vs generative AI model vs RAG solution
  • Responsible AI principle vs technical mitigation
  • Real-time prediction vs batch processing

AI Workload and Azure Service Selection

Scenario keywordWorkload typeBest Azure fitWatch for
Predict house price, sales amount, temperatureRegressionAzure Machine LearningNumeric output
Predict churn, fraud yes/no, product categoryClassificationAzure Machine LearningDiscrete class output
Group similar customers without labelsClusteringAzure Machine LearningUnsupervised learning
Detect unusual login, abnormal sensor readingAnomaly detectionAzure AI services or Azure Machine Learning“Unusual” does not always mean fraud
Identify objects in photosComputer visionAzure AI Vision or Custom VisionObject detection returns locations
Read printed or handwritten text from imagesOCRAzure AI VisionText extraction, not semantic understanding
Extract fields from invoices, receipts, formsDocument intelligenceAzure AI Document IntelligenceStructured documents and key-value pairs
Detect faces in imagesFace analysisAzure AI FaceIdentification/verification may have access and responsible-use constraints
Analyze sentiment, entities, key phrasesNatural language processingAzure AI LanguageText input
Translate text between languagesTranslationAzure AI TranslatorText-to-text translation
Convert speech to textSpeech recognitionAzure AI SpeechAudio input, text output
Convert text to realistic speechSpeech synthesisAzure AI SpeechText input, audio output
Build chatbot or conversational assistantConversational AI / generative AIAzure AI Foundry, Azure OpenAI, Azure Bot Service, Azure AI LanguageChoose based on whether answers are scripted, grounded, or generated
Search internal documents with AI enrichmentKnowledge mining / searchAzure AI SearchIndex, query, and enrich content
Summarize, draft, classify, reason over promptsGenerative AIAzure OpenAI Service in Azure AI FoundryRequires safety, grounding, prompt design
Detect harmful user-generated contentContent moderationAzure AI Content SafetySafety filter, not a full governance program

Core AI Concepts

TermExam meaningCommon trap
Artificial intelligenceSoftware performing tasks associated with human intelligenceAI is broader than machine learning
Machine learningModels learn patterns from dataNot all AI uses ML
Deep learningNeural-network-based ML, often with many layersOften used for vision, speech, and language
Generative AIProduces new text, images, code, or other contentGenerated output can be incorrect
ModelLearned function used for prediction or generationModel is not the same as dataset
AlgorithmMethod used to train or run a modelAlgorithm is the process, model is the result
FeatureInput variable used by a modelPoor features can limit model quality
LabelKnown target value used in supervised trainingClustering usually has no labels
Training dataData used to learn model patternsCan contain bias or leakage
Validation dataData used to tune and compare modelsDo not treat as final proof of performance
Test dataHeld-out data used for final evaluationShould represent real-world use
InferenceUsing a trained model to produce outputDifferent from training
Batch inferenceRun predictions over many records asynchronouslyGood for scheduled scoring
Real-time inferenceLow-latency prediction for one request or small setGood for apps and APIs
GroundingSupplying source data to guide generated answersHelps reduce hallucination but does not guarantee correctness
PromptInstruction or input to a generative modelPrompt quality strongly affects output
TokenUnit of text processed by a modelNot always the same as a word
EmbeddingNumeric vector representing semantic meaningUsed for similarity search and RAG
Vector searchFinds items with similar embeddingsDifferent from exact keyword match
RAGRetrieval-augmented generationCombines search/retrieval with generation

Responsible AI Principles

Microsoft AI exams frequently test whether you can match a risk or mitigation to the right responsible AI concept.

PrincipleMeansScenario cluesPractical mitigation
FairnessAI should treat people equitablyUnequal outcomes across groupsRepresentative data, bias testing, human review
Reliability and safetyAI should work dependably and avoid harmModel fails in edge cases or unsafe conditionsTesting, monitoring, fail-safe design
Privacy and securityAI should protect data and systemsSensitive data, identity, access, encryptionData minimization, access control, encryption
InclusivenessAI should empower diverse usersAccessibility, different abilities, languagesInclusive design, accessibility testing
TransparencyUsers should understand AI behavior and limitsExplainability, disclosure, confidenceDocumentation, explanations, model cards
AccountabilityPeople remain responsible for AI systemsOwnership, audit, governanceHuman oversight, audit trails, review process

Responsible AI Traps

TrapCorrect exam interpretation
“The model is accurate overall, so it is fair.”Overall accuracy can hide subgroup harm.
“Content filters make generative AI safe.”Filters help, but safety also needs design, testing, monitoring, and human oversight.
“An AI system decides, so nobody is accountable.”People and organizations remain accountable.
“Explainability is the same as privacy.”Explainability supports transparency; privacy protects data.
“More data always reduces bias.”More biased data can reinforce bias.
“Grounding eliminates hallucinations.”Grounding reduces risk but outputs still require validation.

Machine Learning Task Reference

TaskInputOutputUses labels?Example
Binary classificationFeaturesOne of two classesYesFraud/not fraud
Multiclass classificationFeaturesOne of many classesYesProduct category
RegressionFeaturesNumeric valueYesForecast revenue
ClusteringFeaturesGroup assignmentNoCustomer segments
Anomaly detectionFeatures or time seriesNormal/unusualSometimesDetect abnormal device behavior
Object detectionImageLabels plus bounding boxesYesLocate cars in traffic images
Image classificationImageImage-level labelYesCat, dog, or bird
Text classificationTextCategory labelYesSupport ticket routing
Named entity recognitionTextEntity spans and typesPrebuilt or customPerson, location, date
Question answeringQuestion plus knowledge baseAnswerOften grounded in contentFAQ bot

Supervised, Unsupervised, and Reinforcement Learning

Learning typeDescriptionTypical exam examples
Supervised learningLearns from labeled examplesClassification, regression
Unsupervised learningFinds patterns without target labelsClustering, some anomaly detection
Reinforcement learningLearns actions from rewardsRobotics, game playing, optimization scenarios

Evaluation Metrics

Use metric names carefully. AI-901 usually tests concepts, not deep math, but the distinctions matter.

MetricUsed forHigh-yield meaning
AccuracyClassificationShare of predictions that are correct
PrecisionClassificationOf predicted positives, how many were truly positive
RecallClassificationOf actual positives, how many were found
F1 scoreClassificationBalance between precision and recall
Confusion matrixClassificationCounts true positives, false positives, true negatives, false negatives
Mean absolute errorRegressionAverage absolute prediction error
Mean squared errorRegressionPenalizes larger errors more heavily
Root mean squared errorRegressionError measure in original target units
R-squaredRegressionHow much variance the model explains
AUCClassificationAbility to separate classes across thresholds
\[ \text{Accuracy}=\frac{TP+TN}{TP+TN+FP+FN} \]\[ \text{Precision}=\frac{TP}{TP+FP} \]\[ \text{Recall}=\frac{TP}{TP+FN} \]\[ F1=2 \times \frac{\text{Precision} \times \text{Recall}}{\text{Precision}+\text{Recall}} \]

Precision vs Recall Decision Points

Scenario priorityPreferWhy
Avoid false alarmsHigher precisionPositive predictions should be trustworthy
Catch as many true cases as possibleHigher recallMissing positives is costly
Balance bothF1 scoreUseful when classes are imbalanced
Medical screening, safety alertingRecall is often emphasizedFalse negatives can be dangerous
Automatic blocking, fraud accusationPrecision is often emphasizedFalse positives can harm users

Azure Machine Learning Reference

Use Azure Machine Learning when the scenario requires building, training, evaluating, managing, or deploying custom machine learning models.

ComponentPurposeExam clue
WorkspaceTop-level Azure ML resource for assets and collaborationCentral place for ML projects
Data assetVersioned reference to dataReuse training data
Compute instanceManaged development workstationNotebook authoring and experimentation
Compute clusterScalable training computeTrain jobs at scale
NotebooksCode-first experimentationPython, SDK, data science
DesignerVisual drag-and-drop ML pipelinesLow-code pipeline creation
Automated MLAutomatically tries algorithms and settingsQuickly find a good model
JobsTraining or processing runsTrack experiments
ModelsRegistered trained artifactsVersion and deploy trained models
Online endpointReal-time inferenceApp needs immediate prediction
Batch endpointBatch scoringLarge scheduled prediction job
PipelinesRepeatable multi-step workflowData prep, training, evaluation, deployment
Responsible AI dashboardModel assessment and explanation supportError analysis, fairness, explainability

When to Choose Azure Machine Learning

Choose Azure Machine Learning when…Prefer prebuilt Azure AI services when…
You need a custom predictive modelThe workload is common, such as OCR or translation
You have domain-specific labeled dataYou want fast integration with minimal training
You must control training, evaluation, and deploymentYou do not need to design an algorithm
You need MLOps lifecycle managementThe scenario asks for a ready API
You need custom regression/classification/clusteringThe scenario asks for vision, speech, language, or document extraction

Common ML Traps

TrapCorrect answer pattern
Using Azure AI Vision to predict salesUse Azure Machine Learning regression
Using clustering when target labels existUse supervised learning if labels exist
Treating validation data as training dataKeep validation/test sets separate
Deploying a batch endpoint for an interactive appUse an online endpoint
Assuming AutoML removes evaluation needsYou still evaluate, validate, and monitor

Azure AI Services Overview

Azure AI services provide prebuilt APIs for common AI workloads. They are usually the best choice when the exam scenario says “use a prebuilt model,” “minimize custom training,” or “call an API.”

Service familyUse forExamples
Azure AI VisionImage analysis and OCRCaption images, detect objects, read text
Azure AI FaceFace detection and analysisDetect faces, estimate attributes where supported
Azure AI Document IntelligenceStructured document extractionInvoices, receipts, forms, IDs
Azure AI LanguageText analytics and language understandingSentiment, entities, key phrases, PII, custom classification
Azure AI TranslatorText translationTranslate text between languages
Azure AI SpeechAudio and voice workloadsSpeech-to-text, text-to-speech, speech translation
Azure AI SearchSearch and knowledge miningIndex documents, enrich content, vector search
Azure OpenAI ServiceGenerative AI models in AzureChat, summarization, generation, embeddings
Azure AI Content SafetyDetect harmful contentText/image safety classification

Resource and Authentication Concepts

ConceptMeaningExam note
EndpointService URL used by client appsRequired for API calls
KeySecret used to authenticate requestsProtect and rotate keys
Microsoft Entra IDIdentity-based authenticationPrefer for enterprise access control when supported
Managed identityAzure-managed service identityAvoids storing credentials in code
RegionAzure location for the resourceSome capabilities vary by region
Multi-service resourceOne resource for multiple Azure AI servicesSimplifies access for supported services
Single-service resourceDedicated resource for one serviceUseful for isolated management or service-specific needs

Computer Vision Quick Reference

RequirementChooseOutput
Describe contents of an imageAzure AI Vision image analysisCaptions, tags, objects
Classify entire image into categoriesImage classification / Custom VisionImage-level label
Detect and locate multiple itemsObject detection / Custom VisionLabels plus bounding boxes
Read text in imageOCR with Azure AI VisionExtracted text and location
Extract fields from structured business docsAzure AI Document IntelligenceFields, tables, confidence values
Analyze video contentAzure AI Video IndexerTranscripts, scenes, insights
Detect faces in imagesAzure AI FaceFace detection and related analysis

Vision Distinctions

PairDifference
Image classification vs object detectionClassification labels the whole image; detection locates objects with bounding boxes.
OCR vs Document IntelligenceOCR extracts text; Document Intelligence extracts structured fields from documents.
Vision vs Machine LearningVision is prebuilt image analysis; Azure ML is for custom model training.
Face detection vs face identificationDetection finds faces; identification attempts to match identity and is more sensitive.
Tags vs captionsTags are labels; captions are natural-language descriptions.

Document Intelligence Reference

Document taskService capabilityExample
Extract text from pagesOCR/readScan to text
Extract key-value pairsDocument analysis“Invoice Date: 2026-06-01”
Extract tablesLayout analysisRows and columns from forms
Use prebuilt modelsPrebuilt document modelsReceipts, invoices, identity documents
Train for a custom form typeCustom document modelCompany-specific contract format
Automate document workflowDocument Intelligence plus downstream appValidate, route, store extracted data

Document Intelligence Traps

TrapCorrect interpretation
“Read all text from a photo of a sign”OCR may be enough.
“Extract vendor, total, tax from invoices”Use Document Intelligence.
“Understand document meaning and answer questions”May need Azure AI Search and generative AI/RAG.
“Translate a document’s text”Use Translator after extraction, not Document Intelligence alone.

Natural Language Processing Reference

RequirementChooseNotes
Detect sentimentAzure AI LanguagePositive, neutral, negative; may include opinion mining
Extract key phrasesAzure AI LanguageIdentifies main topics
Identify entitiesAzure AI LanguagePeople, locations, organizations, dates, quantities
Detect PIIAzure AI LanguageFinds sensitive personal information in text
Detect languageAzure AI LanguageDetermines input language
Classify support ticketsCustom text classificationRequires labeled examples
Extract domain-specific entitiesCustom named entity recognitionExample: part numbers, policy IDs
Build intent-based conversational appConversational language understandingIntents and entities
Create FAQ-style answersQuestion answeringGrounded in provided knowledge source
Translate textAzure AI TranslatorText-to-text translation
Summarize or generate textAzure OpenAI ServiceGenerative AI, not basic text analytics

Language Service Distinctions

PairDifference
Sentiment analysis vs key phrase extractionSentiment detects emotion/opinion; key phrases detect important topics.
Entity recognition vs key phrasesEntities are typed items; key phrases are important terms.
PII detection vs entity recognitionPII focuses on sensitive personal data.
Language detection vs translationDetection identifies language; translation converts text.
Question answering vs generative chatQuestion answering returns grounded answers from a knowledge source; generative chat can produce broader responses.
Intent vs entityIntent is what the user wants; entity is data needed to fulfill it.

Speech and Translation Reference

RequirementChooseInputOutput
Transcribe audioAzure AI Speech speech-to-textAudioText
Generate spoken audioAzure AI Speech text-to-speechTextAudio
Translate spoken languageAzure AI Speech translationAudioTranslated text or speech
Translate written textAzure AI TranslatorTextText
Enable voice command appAzure AI Speech plus language understandingAudioIntent/action
Create accessible audio contentText-to-speechTextNatural-sounding voice

Speech Traps

TrapCorrect answer
Text translation from English to FrenchAzure AI Translator
Audio transcription from meeting recordingAzure AI Speech speech-to-text
Spoken translation during conversationAzure AI Speech translation
Voice response from chatbotAzure AI Speech text-to-speech
Understanding user intent after transcriptionUse language understanding after speech-to-text

Azure AI Search and Knowledge Mining

Use Azure AI Search when the scenario involves indexing, querying, enriching, or retrieving information from content repositories.

ConceptMeaningExam clue
IndexSearchable structure containing fieldsQuery documents quickly
IndexerPulls data from supported data sources into an indexAutomate ingestion
Data sourceWhere content comes fromBlob storage, databases, documents
SkillsetAI enrichment pipelineOCR, entity extraction, key phrases
Cognitive skillsBuilt-in AI enrichmentsExtract text, translate, detect entities
Custom skillYour own enrichment logicCall custom API/function
AnalyzerControls text processing for searchTokenization, language-aware search
Semantic rankingImproves relevance using semantic understandingBetter result ordering
Vector searchFinds semantically similar contentEmbedding similarity
Hybrid searchCombines keyword and vector searchBetter retrieval coverage
RAGSearch retrieves grounding data for a generative model“Answer from company documents”

Azure AI Search vs Generative AI

RequirementUse Azure AI SearchUse Generative AI
Retrieve matching documentsYesNot by itself
Rank search resultsYesNot primary role
Enrich content during indexingYesSometimes
Generate natural-language answerOften with RAGYes
Ground answers in internal documentsRetrieval layerGeneration layer
Store searchable vectorsYesNo, model creates embeddings but search stores/queries them

Generative AI Reference

Generative AI scenarios on AI-901 usually test vocabulary, architecture, prompt roles, safety, and when to use Azure OpenAI Service or Azure AI Foundry.

ConceptMeaningExam relevance
Large language modelModel trained to process and generate languageChat, summarization, classification, reasoning
Foundation modelGeneral-purpose model adaptable to many tasksUsed as base model
Prompt engineeringDesigning inputs to guide model behaviorImproves relevance and format
System messageHigh-priority instruction that sets behavior“You are a support assistant…”
User messageEnd-user request“Summarize this article…”
Assistant messageModel response in conversation historyMaintains context
TemperatureControls randomness/creativityLower is more deterministic, higher is more varied
Context windowAmount of input/output context the model can considerLong prompts and documents may exceed capacity
EmbeddingsNumeric semantic representationSimilarity search and RAG
Fine-tuningFurther training a model on task examplesDifferent from grounding
GroundingAdding retrieved source content to promptHelps answer from trusted data
HallucinationPlausible but incorrect generated outputKey generative AI risk
Content filteringDetecting/blocking unsafe contentSafety control, not truth verification

Common Generative AI Workloads

WorkloadExample prompt goalAzure capability
Summarization“Summarize this transcript in 5 bullets”Azure OpenAI Service
Drafting“Write a response to this customer email”Azure OpenAI Service
Classification“Classify this ticket as billing, technical, or sales”Azure OpenAI Service or Azure AI Language
Extraction“Extract product names and quantities”Azure OpenAI Service, Language, or Document Intelligence depending on source
Code generation“Create a function that validates input”Azure OpenAI Service
Embeddings“Create vectors for documents”Azure OpenAI Service embeddings
RAG assistant“Answer using only these indexed documents”Azure AI Search plus Azure OpenAI
Image generation“Create an illustration from this description”Generative image model where available

Prompt Message Pattern

[
  {
    "role": "system",
    "content": "Answer only from the provided policy excerpt. If the answer is not present, say you do not know."
  },
  {
    "role": "user",
    "content": "What is the reimbursement deadline?"
  }
]

RAG Decision Flow

StepPurposeAzure service often used
Ingest documentsBring enterprise content into a searchable systemAzure AI Search
Chunk contentSplit long documents into retrievable sectionsApp logic / indexing pipeline
Create embeddingsRepresent text semanticallyAzure OpenAI Service
Store vectorsEnable similarity retrievalAzure AI Search
Retrieve relevant chunksFind grounding contentAzure AI Search
Build promptCombine instruction, question, and retrieved contextApplication / orchestration
Generate answerProduce natural-language responseAzure OpenAI Service
Cite sources and monitorImprove trust and governanceApp logic, Azure monitoring tools

Generative AI Traps

TrapCorrect interpretation
“Fine-tuning is required to answer from company documents.”Often RAG/grounding is the better first choice.
“A chatbot always requires generative AI.”Simple FAQ or intent bots can use question answering or language understanding.
“Embeddings generate final answers.”Embeddings support retrieval and similarity; generation is separate.
“Content filters ensure factual accuracy.”Filters target unsafe content, not correctness.
“More creative output is always better.”Business workflows often need deterministic, grounded responses.
“The model remembers private uploaded documents automatically.”Apps must manage retrieval, context, storage, and security.

Conversational AI and Bots

RequirementChooseNotes
Menu-like bot with fixed pathsAzure Bot Service / Bot FrameworkRule-based or scripted conversation
FAQ bot over known contentAzure AI Language question answeringGrounded answers
Bot that detects intent and entitiesConversational language understanding“Book flight” plus date/location
Generative assistant over enterprise documentsAzure AI Foundry / Azure OpenAI + Azure AI SearchRAG pattern
Voice-enabled assistantSpeech + language/generative AISpeech-to-text and text-to-speech
Multi-channel botAzure Bot ServiceConnect to chat channels

Intent and Entity Example

User utteranceIntentEntities
“Book a table for four tomorrow at 7 PM”Make reservationParty size: four; date: tomorrow; time: 7 PM
“Cancel my order 12345”Cancel orderOrder ID: 12345
“What is the refund policy?”Ask policy questionPolicy topic: refund

Security, Privacy, and Governance Basics

ControlWhat it protectsExam scenario
AuthenticationVerifies caller identityApp calling an AI API
AuthorizationControls allowed actionsRestrict who can manage models or indexes
Managed identityAvoids embedded secretsAzure service securely calls another service
Key rotationReduces risk from exposed keysAI service key compromised
Network controlsLimits service exposurePrivate enterprise workloads
EncryptionProtects data at rest/in transitSensitive documents or prompts
Data minimizationReduces privacy exposureDo not send unnecessary PII
Logging and monitoringDetects issues and supports auditTrack failures, latency, unsafe outputs
Human reviewAdds oversight for high-impact decisionsApprovals, escalations, appeals
Content safetyDetects unsafe contentUser-generated or generated content

Exam Scenario Shortcuts

If the question says…Think…
“No labeled data”Clustering or unsupervised approach
“Predict a number”Regression
“Predict a category”Classification
“Find unusual values”Anomaly detection
“Bounding boxes”Object detection
“Extract text from image”OCR
“Extract totals from invoices”Document Intelligence
“Translate text”Translator
“Transcribe audio”Speech-to-text
“Generate spoken response”Text-to-speech
“Detect sentiment”Azure AI Language
“Find people, locations, organizations”Named entity recognition
“Remove or detect personal data”PII detection
“Index and search documents”Azure AI Search
“Answer from internal documents”RAG with Azure AI Search and Azure OpenAI
“Train a custom model”Azure Machine Learning
“Low-code ML pipeline”Azure Machine Learning designer
“Automatically select ML algorithm”Automated ML
“Deploy for immediate app calls”Online endpoint
“Score many records overnight”Batch endpoint
“Unsafe text/image detection”Azure AI Content Safety
“Explain why a model predicted something”Transparency/explainability
“Unequal impact across demographic groups”Fairness
“Who is responsible for the AI decision?”Accountability

High-Yield Comparison Tables

Azure AI Services vs Azure Machine Learning vs Azure OpenAI

NeedAzure AI servicesAzure Machine LearningAzure OpenAI Service
Prebuilt vision, speech, language APIsBest fitNot primarySometimes
Train custom predictive modelNot primaryBest fitNot primary
Manage ML experiments and deploymentsNoBest fitNo
Generate natural-language textLimitedNoBest fit
Create embeddingsNoNot primaryBest fit
Analyze documents with forms/fieldsDocument IntelligencePossible custom approachPossible but not primary
Build RAG answer systemSearch/Language componentsNot primaryGeneration component
Need minimal custom model trainingBest fitLess likelyBest fit for generative tasks

Azure AI Language vs Azure OpenAI

RequirementBetter fit
Deterministic sentiment analysisAzure AI Language
Named entity recognitionAzure AI Language
PII detectionAzure AI Language
Custom text classification with labelsAzure AI Language
Open-ended summarizationAzure OpenAI
Drafting new contentAzure OpenAI
Conversational reasoning over contextAzure OpenAI
FAQ over curated source contentAzure AI Language question answering or RAG, depending on complexity
RequirementBest fit
Read text from imageOCR
Extract fields from formsDocument Intelligence
Search many documentsAzure AI Search
Enrich documents during indexingAzure AI Search skillset
Answer questions over documentsAzure AI Search + generative AI
Convert scanned documents into searchable textOCR plus Azure AI Search

Compact Review Checklist

Before exam day, confirm you can:

  • Match classification, regression, clustering, and anomaly detection to scenarios.
  • Explain features, labels, training, validation, testing, and inference.
  • Choose Azure Machine Learning for custom model lifecycle tasks.
  • Choose the right prebuilt Azure AI service for vision, language, speech, translation, and documents.
  • Distinguish OCR from Document Intelligence.
  • Distinguish image classification from object detection.
  • Distinguish Speech from Translator.
  • Distinguish Azure AI Search from Azure OpenAI Service.
  • Explain RAG, embeddings, grounding, tokens, and prompt roles.
  • Identify responsible AI principles from scenario clues.
  • Recognize security basics: endpoint, key, managed identity, authorization, privacy, and monitoring.
  • Avoid assuming that generative AI outputs are factual, unbiased, private, or safe without controls.

Practical Next Step

Use this Quick Reference as a checklist, then practice with scenario-based AI-901 questions that force you to choose the correct Azure service, AI workload type, metric, and responsible AI principle under exam-style wording.

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