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.
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Question: Given Relationship: 'be president of', Sentence: 'When Barack Obama became the 44th president of United States , there was a sense of ecstasy , joy and relief in virtually every country of the world , except in Pakistan , Iraq and Afghanistan .'

Answer: president


Question: Given Relationship: 'arrive in', Sentence: 'Gauguin arrived in Arles by train early on 23 October .'

Answer: arrived


Question: Given Relationship: 'be city of', Sentence: 'Hamburg is the second largest city in Germany and the Hamburg Harbor is its principal port .'

Answer:
city