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: Tom sat at home as if he hadn't a care in the world. Sentence2: His peace was disturbed by a ringing phone. Sentence3: It was the school. Sentence4: He had forgotten to pick up his son. Sentence5: Tom drove quickly to the school to pick up his son.
Output:
Son, The school, Tom