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

Example Input: Who played the character Gene Hunt in the UK TV series 'Life on Mars' and 'Ashes to Ashes'?
Example Output: life on mars

Example Input: Christian Grey is a character in what recent book trilogy?
Example Output: christian grey

Example Input: Who won the 2010 Wimbledon Men's Singles title?
Example Output:
2010 wimbledon championships