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

Input: Consider Input: Which group of the 1970's featured Tony Iommi on guitar, Geezer Butler on bass and Bill Ward on drums?

Output: geezer butler


Input: Consider Input: What is the largest city in Bavaria?

Output: bavaria


Input: Consider Input: Who composed the 'Brandenburg Concertos'?


Output: brandenburg concertos