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

Example Input: What hit song by the Crash Test Dummies comprised four three-letter words all containing the same letter?
Example Output: crash test dummies

Example Input: Which analgesic drug, first isolated in 1804, was named after the Greek god of dreams ?
Example Output: analgesic

Example Input: Who married Brooke Shields in 1997?
Example Output:
brooke shields