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: I needed to get groceries yesterday. Sentence2: I walked to the store instead of driving. Sentence3: On the way, I thought about what I needed to buy. Sentence4: I took my list into the store with me. Sentence5: I bought everything on the list, and had trouble carrying it home.

Output: I (myself)

Input: Consider Input: Sentence1: Fred carefully unhitched the rented trailer. Sentence2: As he went to strap on the chain he noticed a missing link! Sentence3: He ducked under the trailer to find the rest of the chain. Sentence4: Fred hadn't properly set the brake and it rolled backwards. Sentence5: He slowly starved to death and was eaten by wild animals.

Output: Fred

Input: Consider Input: Sentence1: Sierra was playing with her cat in the living room. Sentence2: She was petting the cat's fur when she noticed some little black dots. Sentence3: Upon closer inspection she realized her cat had fleas. Sentence4: She made an appointment with the vet right then. Sentence5: The bugs cleared up quickly with some medication.
Output: Sierra, Fleas, Vet, Cat