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: Jayla was browsing at the library with her son. Sentence2: There was a man at the library. Sentence3: The man was in the children's section. Sentence4: He was staring at the children. Sentence5: Jayla told the clerk to watch the man.
Example Output: Clerk, Jayla, Children, Her son, A man

Example Input: Sentence1: Gareth loved animals. Sentence2: His favourite animal was the Rhino. Sentence3: He felt so sad that they were going extinct. Sentence4: Gareth decided to move to Africa to help Rhinos. Sentence5: He adopted a Rhino called Mahimba who became his best friend.
Example Output:
Mahimba, Gareth