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

Ex Input:
What is the SI unit of capacitance?

Ex Output:
capacitance


Ex Input:
Grace Anna Goodhue was the wife of which US President?

Ex Output:
grace coolidge


Ex Input:
What was the nickname of American Civil War General Thomas Jackson?

Ex Output:

american civil war