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: Consider Input: Sentence1: Ken had just bought a new computer game. Sentence2: But he could not get it to work! Sentence3: So he called a smart friend over to help him install it. Sentence4: His friend got it figured out in no time. Sentence5: Soon the two boys were gaming together happily!

Output: Ken, Friend

Input: Consider Input: Sentence1: Matt and Sarah were married only a month ago. Sentence2: They were so happy getting used to the married life. Sentence3: At least they were happy until Matt's mom moved in. Sentence4: She treated Matt and Sarah both like children. Sentence5: Thanksgiving was awkward this year after Matt kicked her out.

Output: Sarah, Matt, Matt's mom

Input: Consider Input: Sentence1: Mike greeted the receptionist with a smile. Sentence2: The receptionist was not so kind. Sentence3: She reminded Mike his paperwork was due yesterday. Sentence4: Mike just laughed and changed the subject. Sentence5: That afternoon, Mike was summoned to his boss's office.
Output: Mike, Receptionist, Boss