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

[Q]: Who directed the film Black Swan (in ballet)?
[A]: black swan


[Q]: Richard Addinsell's most famous piece of music was used in the 1941 film 'Dangerous Moonlight', what is its title?
[A]: dangerous moonlight


[Q]: Who wrote the musical Can Can?
[A]:
can-can