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.

Example 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.
Example Output: Friends, Bob

Example Input: Sentence1: Barry recently had to take a reading test for college. Sentence2: Barry was nervous, as he did not know what was on the test. Sentence3: However, as Barry was taking the test, he realized how much he knew. Sentence4: As the test went along, Barry felt more confident about it. Sentence5: Barry knew that he had passed the reading test he took.
Example Output: Barry

Example Input: Sentence1: Lucy sat at the police station. Sentence2: She'd been lost and a kind stranger brought her here. Sentence3: She sat with puffy swollen tear stained eyes waiting on her grandpa. Sentence4: An officer gave her a soda while she waited. Sentence5: She was so happy to see grandpa when he arrived, she knocked it over.
Example Output:
Grandpa, Lucy, Kind stranger, Officer