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: Cooper took his laptop with him every where. Sentence2: While at work today Cooper realized he didn't have his laptop. Sentence3: Cooper had a lot of important work on his laptop that he needed. Sentence4: Cooper started looking everywhere for it. Sentence5: Cooper found his laptop at the coffee shop he was at earlier.
Cooper