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: Consider 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.

Output: Friends, Bob

Input: Consider Input: Sentence1: On a Friday night, Bobby wanted to hang out with his friends. Sentence2: All of his friends were busy tonight though. Sentence3: So Bobby made imaginary friends. Sentence4: Bobby hung out with his imaginary friends. Sentence5: Later Bobby went to sleep and was happy with his new squad.

Output: Friends, Imaginary friends, Bobby

Input: Consider Input: Sentence1: Jamie went to Jamaica and smoked some weed. Sentence2: He met Bob Marley's former friend. Sentence3: They talked about reggae together. Sentence4: Jamie realized the other man was too high. Sentence5: He got him a glass of water to calm down a bit.
Output: Jamie, Bob marley's former friend