You will be given a definition of a task first, then some input of the task.
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: A puppy was following me as I walked along the road. Sentence2: I didn't want it to follow me to school, so I threw a rock far away. Sentence3: The puppy ran after the rock. Sentence4: Meanwhile, I ran in the other direction, away from the puppy. Sentence5: I never saw the puppy again.
Output:
I (myself), Puppy