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.

Ex Input:
Sentence1: My wife used the vacuum cleaner today. Sentence2: It is very noisy. Sentence3: Our cat hates it. Sentence4: She hid under the bed for an hour after the vacuuming stopped. Sentence5: She slowly came out and is fine now.

Ex Output:
Our cat, My wife

Ex Input:
Sentence1: Martha sat quietly on the subway as she waited for her stop. Sentence2: An elderly woman boarded the train and held onto the subway rail. Sentence3: Martha felt bad. Sentence4: She stood up and offered her seat to the elderly woman. Sentence5: The woman thanked Martha enthusiastically.

Ex Output:
Woman, Martha, Elderly woman

Ex Input:
Sentence1: Frederick wanted to bake a pie for his family. Sentence2: He wasn't particularly great at baking but wanted to give it a try. Sentence3: After preparing the pie he set the timer and put the pie in the oven. Sentence4: Halfway through baking the timer broke and never alarmed. Sentence5: Frederick forgot about the pie and it burned up in the oven.

Ex Output:
Frederick, Family