10851
The merger of the Mass Transit Railway (  MTR  ) with the Kowloon - Canton Railway ( KCR ) was an important milestone in the railway development of  Hong Kong  said Henry Tang chief secretary for Administration of the Hong Kong Special Administrative Region government at a ceremony here marking the event .
 city of headquarters: MTR, Hong Kong
Given a phrase that describes the relationship between two words, extract the words and the lexical relationship between them. The output format should be "relation1: word1, word2; relation2: word3, word4". 
Option: cities of residence, top members employees, members, alternate names, origin, state or provinces of residence, title of person, spouse, city of headquarters, NA, founded by, state or province of headquarters, employee of, countries of residence, country of birth, founded, subsidiaries, country of headquarters 
Text: {0} 
Answer:
 city of headquarters: MTR, Hong Kong