From the given sentence, extract the phrase (often noun or verb) that carries the given relationship. The generated phrase should be present in the sentence.

Ex Input:
Given Relationship: 'be friend of', Sentence: 'I have always taken the position that Israel is a friend of the United States , and that friends should always stand up for one another , even in difficult times .'

Ex Output:
friend


Ex Input:
Given Relationship: 'be chairman of', Sentence: 'Warner , an influential Republican and former chairman of the Senate Armed Services Committee , on Thursday recommended that Bush announce the beginning of a U.S. withdrawal in mid-September and that those troops should be back in the United States by Christmas .'

Ex Output:
chairman


Ex Input:
Given Relationship: 'be president of', Sentence: 'Robert Mugabe became Zimbabwe 's first president after the establishment of majority rule and the official granting of independence from Britain in 1980 .'

Ex Output:

president