16673
Further experimentation by Rutherford found that the nuclear mass of most atoms exceeded that of the protons it possessed ; he speculated that this surplus mass was composed of previously-unknown neutrally charged particles , which were tentatively dubbed " neutrons " .
 person: Rutherford
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: Rutherford 
Answer:
 person: Rutherford