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

Example Input: Which country mainly makes up the Horn of Africa?
Example Output: africa

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

Example Input: Who were Aramis, Porthos and Athos?
Example Output:
athos