You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
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.

Sentence1: My dog was bored. Sentence2: I was working all day so I couldn't spend time with him. Sentence3: When I finished work I decided to play with my dog. Sentence4: He was so happy to finally have some fun! Sentence5: Alas, he fell sick and died.
Solution: I (myself), Dog
Why? There is only two characters in given story, i.e., I (myself) and dog.

New 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!
Solution:
Dentist, Dentists, Ava