7681
The discovery of the oil field in east  China  's Bohai Bay was announced by  CNPC  in May and is said to be the biggest oil discovery in China in the last 30 years .
 country of headquarters: China, CNPC
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:
 country of headquarters: China, CNPC