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

Example Input: Which actress played Arwen in the trilogy of films?
Example Output: arwen

Example Input: Aaron Copeland wrote a ballet about which American folk hero?
Example Output: aaron copeland

Example Input: Which executive producer of Dream On is well known for films such as Trading Places?
Example Output:
dream on