Detailed Instructions: 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.
Problem:Sentence1: Joan's son ran in the house saying a squirrel had bitten him. Sentence2: Worried, Joan called the doctor. Sentence3: The doctor said she should catch the squirrel, which could be rabid. Sentence4: Joan chased the squirrel around the yard and up a tree. Sentence5: When she fell, she ended up at the doctor without the squirrel.
Solution:
Joan, Joan's son, Squirrel, Doctor