37886
In late 1906 , Lee de Forest had invented the three-element ( triode ) " grid Audion " vacuum-tube .
 person: Lee de Forest
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
 Entities: Lee de Forest 
Answer:
 person: Lee de Forest