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:
a mathematician's apology is a book about mathematics which was written in 1940.

Ex Output:
a mathematician's apology


Ex Input:
jesse helms (october 18, 1921 - july 4, 2008) was a senator from north carolina.

Ex Output:
jesse helms


Ex Input:
nina companeez (born 26 august 1937 – 9 april 2015) was a french screenwriter and film director.

Ex Output:

nina companeez