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

Ex Input:
Who wrote the novels About A Boy, How To Be Good and High Fidelity?

Ex Output:
how to be good


Ex Input:
Who hosted Call My Bluff?

Ex Output:
call my bluff


Ex Input:
Of all the actors who played Doctor Who in the TV series of the same name, who appeared in the most episodes?

Ex Output:

doctor who