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.

Example Input: Sentence1: Sam went on his weekly fishing trip with his dad. Sentence2: Usually Sam only catches small fish, but this time it was different. Sentence3: The fish almost pulled him off balance, but he caught it. Sentence4: The fish was longer than he was tall, and it was his biggest catch. Sentence5: Sam and his dad got a picture with the fish and cherished the memory.
Example Output: Dad, The fish, Sam

Example 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.
Example Output: Isaac, Friends, Mother

Example Input: Sentence1: Kay met Chad online. Sentence2: Kay and chad grew close. Sentence3: Kay decided to move across the country to live with Chad. Sentence4: Kay rented a Uhaul and drove across the country. Sentence5: Kay now happily lives with Chad.
Example Output:
Kay, Chad