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: Ava needed a root canal badly- she was always in pain. Sentence2: But she was terrified of dentists! Sentence3: Finally the agony drove her to make an appointment. Sentence4: The dentist was very kind when she arrived, and put her at ease. Sentence5: And to her shock, the root canal didn't hurt one bit!

Output: Dentist, Dentists, Ava

Input: Consider Input: Sentence1: Sue had to make brownies for her party. Sentence2: Halfway through baking she realized that she had no eggs. Sentence3: Sue walked to her neighbor's to borrow two. Sentence4: The neighbor greeted her at the door. Sentence5: He gave her two eggs and told her to not worry about repayment.

Output: Sue, Neighbor

Input: Consider Input: Sentence1: David dropped out of high school. Sentence2: He did not know what to do with his life. Sentence3: He impregnated his girlfriend and did not have money. Sentence4: Jobs did not want him. Sentence5: He decided to join the army.
Output: His girlfriend, David