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

Ex Input:
Chris Martin is the lead vocalist and rhythm guitarist with which group?

Ex Output:
chris martin

Ex Input:
Who achieved fame for his ,'Confessions Of An English Opium Eater'?

Ex Output:
confessions of an english opium-eater

Ex Input:
Who played the chimney sweep Bert in the 1964 film 'Mary Poppins'?

Ex Output:
mary poppins