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

Ex Input:
Which former Blue Peter presenter died in April 2004, aged 41?

Ex Output:
blue peter


Ex Input:
Which American city has baseball-playing 'Dodgers'?

Ex Output:
los angeles dodgers


Ex Input:
In 2013 Yahoo purchased which pictures and video microblogging website business that was founded in 2007 in New York City by David Karp?

Ex Output:

yahoo!