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: John didn't get a lot of sleep before work. Sentence2: At work he fell asleep at his desk. Sentence3: He started snoring very loudly. Sentence4: His boss heard him and came over. Sentence5: He got written up for falling asleep at work.
Output:
John, His boss