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

Ex Input:
In which war was the Battle of Bunker Hill?

Ex Output:
battle of bunker hill


Ex Input:
What was the currency of Austria before the Euro?

Ex Output:
austria


Ex Input:
Which 1975 book by the Australian philosopher Peter Singer is considered to be the founding philosophical statement of the animal rights movement?

Ex Output:

peter singer