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.
Input: Sentence1: Amy was outside at the dentist office. Sentence2: It was 5 o'clock and the doors were locked. Sentence3: She called them to find out how she would get in the building. Sentence4: She was afraid she missed them when they didn't answer immediately. Sentence5: Finally they answered and told her she was at the wrong door.
Output:
Amy