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: Natasha cared a lot about her grades. Sentence2: In order to get an A in gym class, she would need to climb the rope. Sentence3: Natasha was nervous, as she wasn't very strong. Sentence4: She decided to start lifting weights. Sentence5: On the day of the test, Natasha climbed to the top!

Output: Natasha

Input: Consider Input: Sentence1: Felix was highly interested in life in the colonial United States. Sentence2: He loved going to reenactments and colonial fairs. Sentence3: He studied their ways of making goods and doing services. Sentence4: Eventually he found employment in colonial Williamsburg. Sentence5: It was a good educational opportunity, and a chance to share his love.

Output: Colonial williamsburg, Felix, Colonial united states

Input: Consider Input: Sentence1: Mark has always loved adventure. Sentence2: One day he and his friends are riding their bikes down a steep hill. Sentence3: Riding in front of others, Mark slips and falls. Sentence4: His leg is broken and he now needs to use crutches. Sentence5: Mark decides to stop living so adventurously.
Output: Others, Friends, Mark