Instructions: 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.
Input: Sentence1: Shadow the dog really wanted to go for a walk. Sentence2: She rubbed her head against her owner's legs. Sentence3: She tried to get his attention by making strangled barking sounds. Sentence4: She sat impatiently by her leash and pawed at it. Sentence5: Eventually her master couldn't ignore her and Shadow got her walk.
Output:
Shadow, Owner, Shadow the dog