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: Jack had an old toy box in his room. Sentence2: He used to hide his favorite toys inside of it. Sentence3: One day he decided to hide inside the toy box. Sentence4: He became locked in the box and couldn't get out. Sentence5: His mother was able to help him climb out of the toy box.
Output:
His mother, Jack