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 had a problem,he was a thief. Sentence2: John saw money his mother had left on the table. Sentence3: John took it for snacks. Sentence4: There was no money for dinner. Sentence5: Jack's snacks became his dinner.
Output:
John, Jack, Mother