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

Example Input: Chris Martin is the lead singer with which band who had several hits in the 2000s?
Example Output: chris martin

Example Input: Name the actress, she died in August 2002, who played the part of 'Madame Edith Artois' in the TV series 'Allo, Allo'?
Example Output: edith artois

Example Input: Which scientist discovered the elements Calcium, Barium and Potassium?
Example Output:
barium