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: Tony decided to make lemonade the old-fashioned way. Sentence2: He brought out some lemons, water, and sugar. Sentence3: He squeezed the lemons until he thought his hands would fall off. Sentence4: He then added some water, and a generous amount of sugar. Sentence5: Tony tasted his lemonade and decided he wanted to be a chef someday.

Ex Output:
Tony

Ex Input:
Sentence1: Isaac was prone to bouts of depression. Sentence2: He never made many friends, and was usually found by himself. Sentence3: He imagined that no one would miss him and began to cry. Sentence4: His mother heard his sobbing and came to find out what was wrong. Sentence5: She encouraged him that she would miss him if he disappeared.

Ex Output:
Isaac, Friends, Mother

Ex Input:
Sentence1: I registered for an English class in college. Sentence2: When I went to buy books, the book for this class was an encyclopedia. Sentence3: I paged through it and the encyclopedia was poorly-written. Sentence4: I got a very bad feeling and dropped the class. Sentence5: I later learned this this course was a disaster.

Ex Output:
I (myself)