83205
However , the same definition may be extended to two-body problems such as Kepler 's problem , by taking as the reduced mass of the two bodies and " r " as the vector between the two bodies .
 person: Kepler
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: Kepler 
Answer:
 person: Kepler