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: Mark and Jim went out fishing so they could have something for dinner. Sentence2: The two worked hard but it was hot and there were no fish. Sentence3: Jim suggested trying a new spot in the shade. Sentence4: The new spot worked and they brought in half a dozen fish. Sentence5: That night they had a delicious meal they were proud of.
Example Output: Jim, Mark

Example Input: Sentence1: Yusuf was startled by a loud knocking at his door at a late hour. Sentence2: He wasn't expecting company, and grabbed his gun. Sentence3: A shivering woman greeted him when he opened the door. Sentence4: She had hit black ice and her car had slid off the road. Sentence5: Yusuf called a tow truck for her, and let her warm up in his house.
Example Output: Yusuf, Woman

Example Input: Sentence1: Tom was the class clown in high school. Sentence2: There was a talent show at his school. Sentence3: He looked forward to the talent show. Sentence4: He created an act for the show. Sentence5: He performed the act at his high school talent show.
Example Output:
Tom