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

Example Input: 'Highway 61 Revisited' and 'Blood On The Tracks' were both albums released by which popular singer?
Example Output: highway 61 revisited

Example Input: In which classic T.V. crime series did Captain Frank Furillo appear ?
Example Output: frank furillo

Example Input: During the 2012 London Olympic Games, which Royal Palace was used as a venue?
Example Output:
2012 summer olympics