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: Dennis decides he wants more hours at work. Sentence2: He decides he doesn't want to ask his boss for more hours. Sentence3: So, instead he just dawdles at night before he clocks out. Sentence4: But his boss is taking notice and tells him to stop. Sentence5: Dennis decides to ask his boss for more hours.
Dennis, Boss