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: Sam was in high-school, so he wasn't old enough to drink. Sentence2: All his friends loved to throw parties and drink all night. Sentence3: Sam really wanted to party with his friends, so sneaked out one night. Sentence4: At the party, Sam saw all his drunk friends acting really stupid. Sentence5: It disgusted Sam, so he stayed sober and drove his friends home.
School, Friends, Sam