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

Ex Input:
The plays 'The Barber of Seville' and 'Marriage of Figaro' were written by whom?

Ex Output:
the marriage of figaro

Ex Input:
Which singer provides the voice for Chef in South Park?

Ex Output:
chef

Ex Input:
Who bought CBS in 1929 and remained on the board until 1983?

Ex Output:
cbs