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: Beth had a wonderful young son. Sentence2: Beth was a single mother. Sentence3: Beth's son begged her to buy a pet for their home. Sentence4: She allowed him to have a pet gerbil. Sentence5: Beth's son loved the gerbil and was happy.
Output:
Beth