Detailed Instructions: In this task, you're given a story (which contains five sentences only). Your task is to find all the characters which are available in the given story.
Q: Sentence1: Luis was eating an apple pie. Sentence2: Then he found something in the pie. Sentence3: It was a fly. Sentence4: Luis complained to the waitress. Sentence5: The waitress picked out the fly and asked him what the problem was.
A:
Fly, Luis, Waitress