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: Tim had his phone in class. Sentence2: He forgot to put it on silent. Sentence3: A friend kept trying to text him. Sentence4: Tim was caught fiddling with it. Sentence5: The teacher took it away for the day.
Tim, Teacher, A friend