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: Jack decided to take his dog for a walk. Sentence2: He changed his mind when he saw it was raining hard outside. Sentence3: His dog had already got excited and made him put on his shoes anyway. Sentence4: Jack went out grudgingly, but was soon romping through puddles. Sentence5: Dog and master returned home quite wet and muddy, but very happy.
Jack, His dog