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

Ex Input:
The Cato Street Conspiracy was a plot to kill which British Prime Minister?

Ex Output:
prime minister of the united kingdom

Ex Input:
Which horse won the 2009 Epsom Derby?

Ex Output:
2009 epsom derby

Ex Input:
Before it was moved to the purpose-built city of Brasilia, what city was Brazil's capital?

Ex Output:
brazil