You will be given a definition of a task first, then some input 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: Robert wanted to impress his girlfriend. Sentence2: He signed up at a gym to improve his muscle mass. Sentence3: He worked and worked for weeks. Sentence4: When he was all buffed up and proud he paraded for her. Sentence5: She told him shyly that she preferred men without too many muscles.
Output:
Robert, Girlfriend