Definition: 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.
Input: Sentence1: Jimmy wanted to play at the playground. Sentence2: Jimmy's mom told him he needed to clean his room first. Sentence3: Jimmy disobeyed and went to the playground without cleaning his room. Sentence4: Mom discovered Jimmy's room still messy. Sentence5: Jimmy was grounded when he got home.
Output:
Jimmy, Jimmy's mom