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 chairman of', Sentence: 'President Bush named his top economic advisor , Ben Bernanke to replace economic legend Alan Greenspan as the chairman of the Federal Reserve .'

Ex Output:
chairman


Ex Input:
Given Relationship: 'be key to', Sentence: 'As present processes are thought to explain all past events , the Uniformitarianism slogan is " the present is the key to the past . "'

Ex Output:
key


Ex Input:
Given Relationship: 'be color of', Sentence: 'Since the typical colors of Christmas wreaths are green , many have designs based on plants usually associated with this occasion : holly , fir and acorns .'

Ex Output:

colors