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

Ex Input:
Cassandra, Grizabella and Skimbleshanks are all characters in which Andrew Lloyd Webber musical?

Ex Output:
andrew lloyd webber


Ex Input:
What book was written by Alexandre Dumas about Edmond Dantes' imprisonment in the Chateau d'If?

Ex Output:
alexandre dumas


Ex Input:
Isabella 'Bella' Swan is the lead character in which series of vampire books?

Ex Output:

bella swan