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: Ben got a new puppy. Sentence2: He was very excited to show him around. Sentence3: He went to the park to play ball. Sentence4: He went for a long walk around his neighborhood. Sentence5: But when it was time to actually train him, he was exhausted.
Puppy, Ben