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

[EX Q]: Which analgesic drug, first isolated in 1804, was named after the Greek god of dreams ?
[EX A]: analgesic

[EX Q]: What horse won the 2009 Grand National?
[EX A]: 2009 grand national

[EX Q]: Who played Aragorn in the film Lord of the Rings?
[EX A]:
aragorn