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: Consider Input: Sentence1: John did not know how to roller skate. Sentence2: His friend said that he would teach him. Sentence3: They spent all day practicing skating. Sentence4: John kept trying and got very good. Sentence5: Now he roller skates all over the neighborhood.

Output: John, Friend

Input: Consider Input: Sentence1: Susie and her friends decided to play graveyard. Sentence2: The girls laid down on the field motionless. Sentence3: All the sudden Susie moved. Sentence4: She ended up losing the game first. Sentence5: Susie laughed but wanted to play again.

Output: Friends, Susie

Input: Consider Input: Sentence1: Missy loves playing ball. Sentence2: All of her friends play too. Sentence3: Missy has a big game tonight. Sentence4: she is nervous about it. Sentence5: Missy wins the game.
Output: Friends, Missy