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

Ex Input:
Which major river has its source at the confluence of the rivers Brigach and Breg in the Black Forest?

Ex Output:
breg


Ex Input:
Who was British Prime Minister from 1922-23, shortly before he died?

Ex Output:
prime minister of the united kingdom


Ex Input:
Clun Forest, Romney and Bluefaced Leicester are all breeds of which animal?

Ex Output:

romney sheep