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.
Example: Sentence1: My dog was bored. Sentence2: I was working all day so I couldn't spend time with him. Sentence3: When I finished work I decided to play with my dog. Sentence4: He was so happy to finally have some fun! Sentence5: Alas, he fell sick and died.
Example solution: I (myself), Dog
Example explanation: There is only two characters in given story, i.e., I (myself) and dog.

Problem: Sentence1: Stan opened the mail one day. Sentence2: He noticed his electric bill was more expensive than usual. Sentence3: He asked everyone in the family if they knew why. Sentence4: His oldest son admitted to never turning off his computer. Sentence5: Stan asked him to start doing so and he obliged.

Solution: Stan, Family, Son