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

Q: Brasilia is the capital but which city in Brazil has the largest population?

A: brazil
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Q: Pirate Edward Teach was better known by what nickname?

A: edward teach
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Q: Who was Fred Astaire's female leading lady in the 1948 film `Easter Parade'?

A:
easter parade
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