2027
In 1637 , René Descartes " invented the convention of representing unknowns in equations by " x " , " y " , and " z " , and knowns by " a " , " b " , and " c " " .
 person: René Descartes
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
 Entities: René Descartes 
Answer:
 person: René Descartes