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

Input: Consider Input: Mr Barkis, Edward Murdstone and Tommy Traddles are all characters in which Charles Dickens novel?

Output: charles dickens

Input: Consider Input: Who composed the opera 'Albert Herring' in 1947?

Output: albert herring

Input: Consider Input: Which river is spanned by the Clifton Suspension Bridge?
Output: clifton suspension bridge