TASK DEFINITION: Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
PROBLEM: Who directed the film `Back To The Future`?

SOLUTION: back to the future

PROBLEM: Which film actor (1895-1926) is known for his films The Four Horsemen, The Sheik and Blood And Sand?

SOLUTION: blood and sand

PROBLEM: Who sang Achy Breaky Heart?

SOLUTION:
achy breaky heart