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: John found a wallet on the street with $180 in it. Sentence2: The owner's contact information was inside. Sentence3: He called him to tell him where he could get his wallet. Sentence4: The man was so happy he gave John a reward. Sentence5: He gave him half the money that was in the wallet!
Output:
Owner, John