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.

Ex Input:
Sentence1: Shawn wanted to get a promotion at work. Sentence2: He decided to take night classes to get certifications. Sentence3: He took online classes 3 days a week. Sentence4: When he got his certification he asked his boss for a raise. Sentence5: His boss agreed to the raise.

Ex Output:
Shawn, His boss

Ex Input:
Sentence1: Isaac was prone to bouts of depression. Sentence2: He never made many friends, and was usually found by himself. Sentence3: He imagined that no one would miss him and began to cry. Sentence4: His mother heard his sobbing and came to find out what was wrong. Sentence5: She encouraged him that she would miss him if he disappeared.

Ex Output:
Isaac, Friends, Mother

Ex Input:
Sentence1: Tina had been wanting her ears pierced for years. Sentence2: She was finally old enough so she was getting it done. Sentence3: As she watched other girls before her she grew more and more scared. Sentence4: Luckily her mom was there to comfort her through it. Sentence5: She got it done and loved it more than she could have imagined.

Ex Output:
Other girls, Mom, Tina