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: I am Chinese. Sentence2: One day I was sitting on the bench in front of my building. Sentence3: A young man came by and said I looked like his father. Sentence4: He was white, however, as was his father. Sentence5: He said I just looked like his dad.

Output: I (myself), Young man

Input: Consider Input: Sentence1: Ava needed a root canal badly- she was always in pain. Sentence2: But she was terrified of dentists! Sentence3: Finally the agony drove her to make an appointment. Sentence4: The dentist was very kind when she arrived, and put her at ease. Sentence5: And to her shock, the root canal didn't hurt one bit!

Output: Dentist, Dentists, Ava

Input: Consider Input: Sentence1: Amy started training to be a gymnast at an early age. Sentence2: She wasn't allowed on the rings with the boys. Sentence3: She was told it'd make her muscles too big. Sentence4: Amy's career was over at 20 years of age from an injury. Sentence5: She regrets abusing her body and stunting her growth now.
Output: Amy, Boys