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

Example Input: Which 20th century British prime minister had the longest surname ?
Example Output: prime minister of the united kingdom

Example Input: Which American screenwriter, producer, director, actor, author and editor, most productive in the 1950's, made Plan 9 From Outer Space, Glen or Glenda and Bride Of The Monster?
Example Output: screenwriter

Example Input: Miranda, Ariel and Umbriel are all moons of which planet in our solar system?
Example Output:
umbriel