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

Example Input: Who wrote the 1939 book The Big Sleep?
Example Output: the big sleep

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: Who worked at Betchley Park in World War II as one of the Enigma codebreakers and became known as the father of modern computer science?
Example Output:
computer science