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

Example Input: Which British composer wrote the music used as the theme for Desert Island Discs  He also wrote the Dambusters march and the Knightsbridge march.?
Example Output: the dam busters

Example Input: The Church of the Savior on Spilled Blood, built on the site of the assassination of Tsar Alexander II, is in which Russian city?
Example Output: church of the savior on blood

Example Input: Which Swedish tennis player never won the men's singles title at Wimbledon, but during the 1980s won the US Open once, the French Open twice and the Australian Open three times?
Example Output:
australian open