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:
silliness is when a person acts like a fool, or shows a lack of good sense or judgment.

Ex Output:
silliness


Ex Input:
angie dickinson (b september 30 1931 near north dakota) is an american movie actress.

Ex Output:
angie dickinson


Ex Input:
the jerusalem artichoke ("helianthus tuberosus"), also called sunroot, sunchoke, earth apple or topinambour, is a species of sunflower native to eastern north america, and found from eastern canada and maine west to north dakota, and south to northern florida and texas.

Ex Output:

jerusalem artichoke