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Mutt and Jeff were two Norwegian spies who worked for the  United Kingdom  and  MI5  and were members of the Double Cross System .
 country of headquarters: United Kingdom, MI5
Given options, please tell me the relationships of all the listed entity pairs.Output format is "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} 
 Entity Pairs:  United Kingdom, MI5 
Answer:
 country of headquarters: United Kingdom, MI5