Given the task definition and input, reply with output. 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: Ulrich had a research paper due in a week. Sentence2: He procrastinated his paper til the last day. Sentence3: Ulrich tried pleading to his teacher for an extended deadline. Sentence4: His teacher agreed to extend the due date at the cost ten points. Sentence5: Ulrich managed to finish the paper and get a good grade.
Teacher, Ulrich