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: Tom had jealousy issues. Sentence2: He found his girlfriend with a strange guy. Sentence3: Tom confronted them both in an angry fashion. Sentence4: They tried to explain to Tom that they were just cousins. Sentence5: Tom knew they were lying.

Ex Output:
Girlfriend, Guy, Tom

Ex Input:
Sentence1: Nicholas was assigned a term paper in his economics class. Sentence2: It was on a topic about which he knew very little. Sentence3: Nicholas spent several days doing in-depth research. Sentence4: He wrote a ten page paper. Sentence5: Nicholas learned about a lot about his new topic.

Ex Output:
Nicholas

Ex Input:
Sentence1: Stella worked for a super demanding boss. Sentence2: He would never give her affirmations for the hard work she did. Sentence3: Stella felt incredibly unhappy with her life. Sentence4: She was certain she deserved more praise for all she did. Sentence5: Stella filed a discrimination claim against her boss.

Ex Output:
Stella, Boss