Given the task definition and input, reply with output. 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: Jake was swimming in the pool at his gym. Sentence2: He felt his shoulder hurting. Sentence3: He was having a cramp! Sentence4: He struggled in pain for minutes. Sentence5: Eventually the cramp went away on its own.
Jake