Q: 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: Jim bought a new laptop. Sentence2: But he realized that his router doesn't support wi-fi. Sentence3: He saw that his neighbor's wi-fi connection was open though. Sentence4: And he decided to use it everyday. Sentence5: A week later, Jim heard a loud knock at his door.
A:
Jim, Knocker