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: I bought bubbles to play with the dog. Sentence2: I blew the bubbles outside in the yard. Sentence3: She chased them around, trying to catch them. Sentence4: She snapped at the bubbles as they floated. Sentence5: After she was tired, we went back in the house.
Example Output: I (myself), Dog

Example Input: Sentence1: Don showed up for his clarinet lesson. Sentence2: He forgot to bring his music. Sentence3: A teacher told him to play some scales. Sentence4: Don really was not ready for that. Sentence5: After that they played some duets with teacher.
Example Output: Don, Teacher

Example Input: Sentence1: Tim's yard would always have trash in it. Sentence2: Wind would bring it around from the neighborhood. Sentence3: After a while Tim got a fence to keep it out. Sentence4: It worked up to a point. Sentence5: Eventually the fence gathered a lot of trash.
Example Output:
Tim