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

Example Input: Who stars in the TV series Californication?
Example Output: californication

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

Example Input: Who was Commander-in-Chief of American ground forces in planning the invasion of France in 1944 and Commander of the US 1st Army on D Day?
Example Output:
normandy landings