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

Ex Input:
Which popular Doctor Who villains, it was revealed in 2011, are to be given 'a rest' by scriptwriters?

Ex Output:
doctor who


Ex Input:
Billy the Kid was a native of which US state?

Ex Output:
billy


Ex Input:
Chihuahua dogs originate from which country?

Ex Output:

chihuahua