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

Example Input: Who plays Isobel Crawley in the UK television series 'Downton Abbey'?
Example Output: downton abbey

Example Input: Which Bob Dylan song begins You got a lotta nerveTo say you are my friend. When I was down, You just stood there grinning?
Example Output: bob dylan

Example Input: Alt, Bock, Dunkel and Helles are German varieties of what?
Example Output:
bock