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: Johnny lost his puppy. Sentence2: He was upset. Sentence3: He put out posters and flyers seeking out the puppy. Sentence4: One of his neighbors recognized the lost dog. Sentence5: Johnny's neighbor reunited him with his puppy.
A:
Puppy, Neighbor, Johnny