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

Example Input: Who has written a series of novels, entitled The Dark Tower, of which the first, in 1982, was entitled, The Gunslinger?
Example Output: the dark tower

Example Input: Who was the first person to sign the American Declaration of Independence?
Example Output: united states declaration of independence

Example Input: What is the name of the actor and singer who voiced the character 'Chef' in the animated series 'South Park' from 1997 to 2006?
Example Output:
chef