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.

Sentence1: Evan wanted to teach his dog to do tricks. Sentence2: But no matter how many times he released commands, it didn't work. Sentence3: His dog just wouldn't listen! Sentence4: Then a friend suggested he reward the dog with treats when it obeyed. Sentence5: With positive reinforcement, Evan's dog was soon doing lots of tricks!
Evan's dog, A friend, Evan