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: Dan's coworker recently made a joke about his weight. Sentence2: Dan decided to approach the coworker about it. Sentence3: Dan expressed his opinions to the coworker about his comments. Sentence4: After talking, Dan's coworker apologized about his insensitive joke. Sentence5: Dan was glad that the coworker understood and respected his feelings.
Dan, Coworker