Generate a topic word for the given sentence. A topic word is usually the name of a person, place, animal, concept or object the sentence is focusing on.

Ex Input:
"if i never see your face again" is the fourth single by maroon 5.

Ex Output:
if i never see your face again


Ex Input:
the global hunger index is a measurement to measure the hunger situation in a country.

Ex Output:
global hunger index


Ex Input:
hong seok-cheon (: ; : , born february 3, 1971) is a south korean model and movie actor.

Ex Output:

hong seok-cheon