Given the task definition and input, reply with output. Given a sentence and two mentions from the text (arguments), indicate a phrase (a verb or noun phrase) that describes the relationship between the provided arguments.

Sentence: 'New York , NY - With the inauguration of Barack Obama as the 44th president of the United States of America , millions of people have flocked to Washington DC to take part in this historical event .', Argument/Subject 1: 'barack obama', Argument/Subject 2: 'unite state of america'
be president of