Definition: 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.
Input: Sentence1: Brian wanted to go to a concert with friends. Sentence2: His boss would not let him have time off. Sentence3: He decided to switch shifts with a coworker. Sentence4: Brian went to the concert and had a great time. Sentence5: Brian now owes his co worker a favor in the future.
Output:
Brian, His boss, Friends