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

[Q]: What country has an official residence called Blair House, kept for guests of the leader of the country?
[A]: blair

[Q]: Who directed the film 'Back To The Future'?
[A]: back to the future

[Q]: Barack Obama was a senator for which state?
[A]:
barack obama