Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.

Ex Input:
What is the only nation state of the Commonwealth of Nations on the mainland of South America?

Ex Output:
commonwealth of nations


Ex Input:
Which popular animated characters, first seen in 1996 include many different characters including ones called Ash Ketchum, Tracy Sketchit and Gar Oak?

Ex Output:
tracy


Ex Input:
What has a moon named Charon?

Ex Output:

charon