Q: 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.
Sentence1: David was a quiet kid. Sentence2: At school, a lot of kids picked on him. Sentence3: One day, a boy was messing with him and insulting him. Sentence4: He got so mad, he decided to fight back. Sentence5: He punched him in the face and the boy didn't bully him ever again.
A:
Boy, Kids, David