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: Del and his friends would have speed-writing competitions. Sentence2: It began as just doing simultaneous quickwrites. Sentence3: But then they started doing time trials. Sentence4: They wanted to see who could write a full story the fastest. Sentence5: Del won in perpetuity when he wrote a full story, one sentence long.
Example Output: His friends, Del

Example Input: Sentence1: Aurelia has been trying to find a hobby for months. Sentence2: Finally a friend recommends that Aurelia try knitting. Sentence3: Aurelia begins by knitting a green sweater. Sentence4: She finds knitting a relaxing way to forget her problems. Sentence5: Aurelia is very happy that she found a good hobby.
Example Output: Friend, Aurelia

Example Input: Sentence1: Kelly wanted to try the new pizza place down the street. Sentence2: As she went inside, she was impressed. Sentence3: They had everything under the sun. Sentence4: Kelly ordered every topping. Sentence5: She couldn't wait to go back.
Example Output:
Kelly