Given the task definition and input, reply with output. 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: Michael rode his bicycle to school one day. Sentence2: He forgot to lock up his bicycle. Sentence3: When he got out of school the bicycle was gone. Sentence4: Michael called the police and described the missing bicycle. Sentence5: A few days later the police called and said they found the bicycle.
Police, School, Michael