Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
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Question: Physics. What is the SI unit for amount of substance?

Answer: amount of substance


Question: Brothers Richard and Simon Mantell played which sport for England in the 2010 Commonwealth Games?

Answer: 2010 commonwealth games


Question: Who wrote the musical Call Me Madam?

Answer:
call me madam