Given the task definition and input, reply with output. 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: Andy always fed his cat human food. Sentence2: His friends would tell him this was bad for the cat. Sentence3: Andy refused to listen to his friends until his cat go sick. Sentence4: He worried for his cat and was foolish for doing it. Sentence5: Now Andy only feeds his cat high quality cat food.
Friends, Andy, Cat