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

Example Input: Which actress played Arwen in the trilogy of films?
Example Output: arwen

Example Input: What is the capital of the US state of California?
Example Output: california

Example Input: The Battle of Palmito Ranch (Hill) was the last major clash of which 19th century war?
Example Output:
battle of palmito ranch