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 boeing monomail was a monoplane instead of a biplane.

Ex Output:
boeing monomail


Ex Input:
tatsuya shiji (志治 達雄, shiji tatsuya, born october 20, 1938) is a former japanese football player.

Ex Output:
tatsuya shiji


Ex Input:
henry david thoreau (july 12, 1817– may 6, 1862) was an american author, naturalist and philosopher.

Ex Output:

henry david thoreau