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

[EX Q]: Who played the character Gene Hunt in the UK TV series 'Life on Mars' and 'Ashes to Ashes'?
[EX A]: life on mars

[EX Q]: Antanananarivo is the capitol of where?
[EX A]: antananarivo

[EX Q]: Which actor famously said the line `Here`s looking at you, kid` in the film `Casablanca`?
[EX A]:
casablanca