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.

Ex Input:
Sentence1: I was playing music on my CD player. Sentence2: I dropped the CD player. Sentence3: It didn't play music anymore. Sentence4: Then I found twenty dollars on the ground. Sentence5: I was able to buy a new CD player.

Ex Output:
I (myself)

Ex Input:
Sentence1: Katherine was at home watching TV. Sentence2: Suddenly she got a phone call. Sentence3: Her dad had had a heart attack and was in the hospital. Sentence4: She quickly went to the hospital to be with him. Sentence5: Luckily, he recovered in a couple of days and was alright.

Ex Output:
Dad, Katherine

Ex Input:
Sentence1: Nancy was taking a karate class. Sentence2: Nancy was gearing to face another individual for a black belt. Sentence3: Nancy was confident that she could beat her opponent. Sentence4: However, her opponent was a great challenge for Nancy. Sentence5: Nancy realized that she was not so tough.

Ex Output:
Another individual, Nancy