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

Ex Input:
Which two brothers had hits with Cathy's Clown and Wake Up Little Susie?

Ex Output:
cathy's clown


Ex Input:
Who was re-elected Prime Minister of Canada in May 2011?

Ex Output:
prime minister of canada


Ex Input:
Which Northampton-born actor will replace David Tennant as the eleventh 'Dr. Who', in 2010?

Ex Output:

dr. who