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: After failing at employment and education, Mike felt lost. Sentence2: He called his parents for help who told him to move back in. Sentence3: Mike's parents were very worried and decided to send him to therapy. Sentence4: Mike then began to see a psychiatrist a few times a week. Sentence5: After the therapy, Mike began to feel better in life.

Ex Output:
Mike, Mike's parents, Psychiatrist

Ex Input:
Sentence1: Jeff is addicted to working out and he goes everyday. Sentence2: He just started a new job that has him working long hours. Sentence3: These long hours prevent him from being able to go to the gym. Sentence4: By the time Jeff gets off work the gym is closed. Sentence5: Jeff went out and bought all the stuff he needs to work out athome.

Ex Output:
Jeff

Ex Input:
Sentence1: Peter was playing tennis with his dad. Sentence2: At first he thought tennis looked easy. Sentence3: But then he began to play! Sentence4: Peter swung and swung, but he missed every ball. Sentence5: He realized tennis was a lot harder than he'd thought.

Ex Output:
Peter, Dad