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 started training to be a gymnast at an early age. Sentence2: She wasn't allowed on the rings with the boys. Sentence3: She was told it'd make her muscles too big. Sentence4: Amy's career was over at 20 years of age from an injury. Sentence5: She regrets abusing her body and stunting her growth now.
Output:
Amy, Boys