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.

[EX Q]: Sentence1: Greta had noticed her son was having trouble focusing in school. Sentence2: Greta took her son to the doctor. Sentence3: The doctor diagnosed the boy with ADHD. Sentence4: The doctor prescribed medicine for him. Sentence5: Greta's son now focuses much better in class.
[EX A]: Greta, Greta's son, The doctor

[EX Q]: Sentence1: We sat down to talk about our problems. Sentence2: He said he wanted to work it out. Sentence3: I told him I didn't know if we could. Sentence4: He said he would start to change. Sentence5: I told him I would try one more time.
[EX A]: I (myself)

[EX Q]: Sentence1: Amy was at the gym. Sentence2: She put her towel and water bottle on a machine and tied her shoe. Sentence3: When she stood a man was on her machine. Sentence4: Amy explained she intended to use this machine. Sentence5: The rude man simply ignored Amy and kept working out.
[EX A]:
Amy, Man