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

Ex Input:
Cilantro is the leaf of which herb?

Ex Output:
cilantro


Ex Input:
What city was the capital of the Confederacy for most of the Civil War?

Ex Output:
confederate states of america


Ex Input:
Which city lies at the confluence of the Blue Nile and the White Nile?

Ex Output:

white nile