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: When Poppy was growing up, she had a very special doll. Sentence2: She took the doll with her everywhere. Sentence3: As she got older, her mother tried to make her give up the doll. Sentence4: Poppy hid the doll so her mother couldn't find it. Sentence5: But Poppy's dog found the doll and chewed it to pieces.

Ex Output:
Poppy, Dog, Mother

Ex Input:
Sentence1: Larry was at a restaurant. Sentence2: He had called a cab to pick him up. Sentence3: It was getting to be almost an hour and no cab arrived. Sentence4: Larry called to ask what was up. Sentence5: It turned out that there was a mix up.

Ex Output:
Larry

Ex Input:
Sentence1: Randy was on a low calorie diet. Sentence2: And it made him feel better than ever. Sentence3: But he was used to eating more often. Sentence4: And he lost control after his mom brought home donuts. Sentence5: Randy regret not sticking to his diet plan.

Ex Output:
Randy, Mom