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.

Example Input: Sentence1: Ken had just bought a new computer game. Sentence2: But he could not get it to work! Sentence3: So he called a smart friend over to help him install it. Sentence4: His friend got it figured out in no time. Sentence5: Soon the two boys were gaming together happily!
Example Output: Ken, Friend

Example Input: Sentence1: When I was a kid there was a lake near my house. Sentence2: Every afternoon I would go outside and throw rocks into the lake. Sentence3: Sometimes there would be ducks in the lake. Sentence4: My parents would always tell me to be careful and not hit the ducks. Sentence5: I really miss living by that lake and seeing those ducks!
Example Output: I (myself), My parents, Ducks

Example Input: Sentence1: Sue was watching a documentary on TV. Sentence2: It was about the negative effect of fluoride. Sentence3: Sue became scared and decided to change her lifestyle habits. Sentence4: She ordered fluoride free toothpaste online. Sentence5: The fluoride free toothpaste came in the mail after a few days.
Example Output:
Sue