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.
Input: Sentence1: Jim was sitting alone in his room, bored. Sentence2: He decided to go out and do something. Sentence3: He tagged the stop sign at the end of his street. Sentence4: A cop sat in his cruiser and watched him do it. Sentence5: Jim got sentenced to six months in juvenile detention.
Output:
Cop, Jim