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: Billy wanted a car. Sentence2: He tried to get a loan but they said he didn't make enough money. Sentence3: Billy couldn't get a better paying job because he didn't have a car. Sentence4: He saved for nine months, until he had enough money for a car. Sentence5: Now that he has a new car and a new job.

Output: Billy

Input: Consider Input: Sentence1: Jon and his father were going hunting in the woods. Sentence2: They saw a deer through the bushes. Sentence3: Trying to keep quiet, they inched towards it. Sentence4: Jon stepped on a branch, and the deer was scared off. Sentence5: The deer would live another day.

Output: A deer, Jon, Father

Input: Consider Input: Sentence1: Mary woke up with a toothache. Sentence2: Her wisdom teeth had been growing in slowly for awhile. Sentence3: They never really hurt much. Sentence4: But they hurt terribly today. Sentence5: She decided she would take ibuprofen and tough out the day at work.
Output: Mary