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: Sean was sitting at his desk. Sentence2: Suddenly, his chair cracked. Sentence3: He looked and saw that the wood had snapped. Sentence4: He grabbed some tools. Sentence5: After a minute, he was able to put the chair back together.
Sean