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

Example Input: Which `brothers` had a number one hit in May 1958 with `All I Have To Do Is Dream`?
Example Output: all i have to do is dream

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

Example Input: Which terrorist gang murdered Christian Democrat leader Aldo Moro?
Example Output:
aldo moro