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

Example Input: Bound for Glory is the 1943 autobiography of which singer-songwriter?
Example Output: bound for glory

Example Input: Who played Lionel Hardcastle in the TV series 'As Time Goes By'?
Example Output: as time goes by

Example Input: In ancient history, which Carthagian general beat the Romans at Cannae in 216 BC?
Example Output:
battle of cannae