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

Example Input: Who has taken over the TV role of Doctor Who, from actor David Tennant?
Example Output: doctor who

Example Input: In which Indian city is Eden Gardens, the second largest test cricket ground in the world?
Example Output: eden gardens

Example Input: Which British author wrote the 1995 Booker winning novel The Ghost Road?
Example Output:
the ghost road