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:
in egyptain mythology sopdet was the goddess of the star sothis.

Ex Output:
sopdet


Ex Input:
hop and go is a 1943 looney tunes short movie directed by u.s. corporal norman mccabe and released to movie theaters by rko radio pictures.

Ex Output:
hop and go


Ex Input:
flerovium is a chemical element.

Ex Output:

flerovium