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In 2018 , computer scientist and biologist Aubrey de Grey found a 1581-vertex , non-4 - colourable unit-distance graph .
 person: Aubrey de Grey
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 person: Aubrey de Grey