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: Consider Input: Sentence1: Yusuf was startled by a loud knocking at his door at a late hour. Sentence2: He wasn't expecting company, and grabbed his gun. Sentence3: A shivering woman greeted him when he opened the door. Sentence4: She had hit black ice and her car had slid off the road. Sentence5: Yusuf called a tow truck for her, and let her warm up in his house.

Output: Yusuf, Woman

Input: Consider Input: Sentence1: A woman was walking. Sentence2: She sat on a bench. Sentence3: There was a man next to her. Sentence4: She realized it was her ex husband. Sentence5: This must have been accidental.

Output: Ex husband, A woman, A man

Input: Consider Input: Sentence1: Amy was an elderly lady. Sentence2: She was in pain and asked her friend for help. Sentence3: Her friend recommended Pilates. Sentence4: Amy began doing Pilates everyday. Sentence5: Amy stopped feeling pain after doing Pilates regularly.
Output: Amy, Her friend