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

Example input: Who was the first American President?
Example output: president of the united states
Example explanation: The question talks about the president of the USA.
Q: Which film actress was born in Germany in 1904, went to America after appearing in the film Blue Angel, and became an American citizen in 1937?
A:
the blue angel