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If the user is able to determine the relevance of each document in the database ( relevant or not relevant ) , then for each query , the complete set of documents is naturally divided into four distinct ( mutually exclusive ) subsets : relevant documents that are retrieved , not relevant documents that are retrieved , relevant documents that are not retrieved , and not relevant documents that are not retrieved .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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