20704
The historic Silk Road starts in Chang'an and goes to Constantinople .
 location: Silk Road; location: Chang'an; location: Constantinople
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: Silk Road, Chang'an, Constantinople 
Answer:
 location: Silk Road; location: Chang'an; location: Constantinople