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

Ex Input:
In which US state are the Catskill Mountains?

Ex Output:
catskill mountains

Ex Input:
Aldebaran is the brightest star in which constellation?

Ex Output:
aldebaran

Ex Input:
Who hosted Call My Bluff?

Ex Output:
call my bluff