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: All Ben's friends had cars, and he wanted one too. Sentence2: He saved every penny he could. Sentence3: By the end of sophomore year, he had earned a few thousand dollars. Sentence4: He bought himself a great used car. Sentence5: Ben was so proud of his new wheels!
Output:
Ben's friends, Ben