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 brinicle is a column of ice that forms in seawater.

Ex Output:
brinicle


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

Ex Output:
sopdet


Ex Input:
the australian classification board is a government agency in australia that controls censorship and classifications.

Ex Output:

australian classification board