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

Ex Input:
Which entertainer uses various names, including Puff Daddy, P. Diddy and Diddy?

Ex Output:
p. diddy


Ex Input:
In which constellation is the star Deneb?

Ex Output:
deneb


Ex Input:
The nuclear disaster site at Chernobyl, to which tourist visits begin/began in 2011, is in which country?

Ex Output:

chernobyl