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: David was whistling in class. Sentence2: The teacher didn't know who was making the noise. Sentence3: She didn't know who to punish. Sentence4: One of the students told the teacher after class that it was David. Sentence5: The next time David whistled, the teacher blamed David.

Output: One of the students, Teacher, David

Input: Consider Input: Sentence1: Calvin was so excited! Sentence2: His friends were coming over for a birthday party. Sentence3: He cleaned his room and decorated the play room. Sentence4: They came over and brought him gifts. Sentence5: He had a great time!

Output: Friends, Calvin

Input: Consider Input: Sentence1: Today I bought a new car. Sentence2: The car was is very nice and I am proud of the car. Sentence3: I worked very hard to earn the money for the new car. Sentence4: I have been very careful when driving my car. Sentence5: I hope my car lasts me a long time because it was very expensive.
Output: I (myself)