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

Example Input: What was the last silent film in which Chaplin's little tramp appeared?
Example Output: chaplin

Example Input: Which Best Picture nominated movie tells the story of US soldier, 'Chris' Kyle?
Example Output: chris kyle

Example Input: What book was written by Alexandre Dumas about Edmond Dantes' imprisonment in the Chateau d'If?
Example Output:
alexandre dumas