Instructions: 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: Sentence1: Doug drove a truck for a living. Sentence2: He wasn't paying attention on the road one day. Sentence3: Doug's truck went off of the road. Sentence4: The truck hit a tree and was damaged. Sentence5: Doug lost his job.
Output:
Doug