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

Example Input: The bells were ringing for Chuck Berry when this song made it to No1. His first and only British No. 1. What song?
Example Output: chuck berry

Example Input: Who released the albums Sentimental Journey, Goodnight Vienna, Bad Boy, Old Wave and Vertical Man between 1970 and 1999?
Example Output: vertical man

Example Input: By what two-word name was the Boeing B-17 aircraft known?
Example Output:
boeing