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

Ex Input:
Which jockey won the 1981 UK Grand National on Aldaniti?

Ex Output:
aldaniti

Ex Input:
What's missing: Magnum Force, The Enforcer, Sudden Impact, and The Dead Pool?

Ex Output:
sudden impact

Ex Input:
Which Arthur wrote 'Death Of A Salesman'?

Ex Output:
death of a salesman