Detailed Instructions: 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.
Problem:Sentence: 'As the third largest city in Vietnam , Hai Phong is the portal to the sea for the northern Red River region that includes Hanoi .', Argument/Subject 1: 'haus phong', Argument/Subject 2: 'vietnam'
Solution:
be city of