9988
Air  Botswana  Corporation is the national airline of Botswana with its head office on the grounds of Sir  Seretse Khama  International Airport in Gaborone .
 country of headquarters: Botswana, Seretse Khama
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: Botswana, Seretse Khama