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:
the usl w-league is a national women's soccer league.

Ex Output:
w-league


Ex Input:
isaac watts (17 july 1674 – 25 november 1748) was an english pastor, preacher, poet, and hymn writer.

Ex Output:
isaac watts


Ex Input:
the airedale terrier (often shortened to "airedale") is a breed of the terrier type, that first came from airedale, a geographic area in yorkshire, england.

Ex Output:

airedale terrier