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: Amy asked her mother for a box of Cookie Crisp. Sentence2: She was surprised when she wasn't allowed. Sentence3: Amy didn't understand why she couldn't have cereal anymore. Sentence4: Apparently cereal had too much sugar. Sentence5: Amy was sad she had to stop eating cereal.
Output:
Amy, Mother