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

Example Input: The headquarters building of which government agency is known as 'The Doughnut' due to its shape?
Example Output: the doughnut

Example Input: According to folklore, what was the name of the monster slain by 'Beowulf'?
Example Output: beowulf

Example Input: Which artist, born in Leeuwarden in 1898, is famous for his optical illusions such as Ascending And Descending, Convex and Concave, and Metamorphosis I?
Example Output:
metamorphosis i