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

Example Input: What's missing: Magnum Force, The Enforcer, Sudden Impact, and The Dead Pool?
Example Output: sudden impact

Example Input: What was the computer's name in 2001: A Space Odyssey?
Example Output: 2001: a space odyssey

Example Input: In which Charles Dickens novel does the character Mr M Choakumchild appear?
Example Output:
charles dickens