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

Ex Input:
Who composed the opera 'Albert Herring' in 1947?

Ex Output:
albert herring


Ex Input:
Who played the title role in the 1955 film 'Davy Crockett, King Of The Wild Frontier'?

Ex Output:
davy crockett


Ex Input:
Which film was based on the story The Sentinel by Arthur C Clarke?

Ex Output:

arthur c. clarke