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: Bob loved to eat fat. Sentence2: His friends thought he ate too much. Sentence3: Indeed, the fat increased Bob's cholesterol intake dramatically. Sentence4: Bob's arteries were becoming clogged. Sentence5: After many years, Bob had a heart attack and died.

Ex Output:
Friends, Bob

Ex Input:
Sentence1: I was feeling really sick. Sentence2: We were lined up for the bathroom. Sentence3: I sat on the floor. Sentence4: The teacher told me to go to her. Sentence5: I walked up to her and vomited on her feet.

Ex Output:
I (myself), Teacher

Ex Input:
Sentence1: Tom was on the high school football team. Sentence2: He was a very competitive guy. Sentence3: He decided to inject steroids to improve his performance. Sentence4: He became a better football player. Sentence5: Tom became happier as a result of his stellar football performances.

Ex Output:
Tom