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: Juan dreamed of becoming a teacher for his whole life. Sentence2: Once he graduated college he couldn't wait to apply for positions. Sentence3: Once he found a job at the local middle school, right away. Sentence4: He quickly set up his classroom and was excited to meet students. Sentence5: Juan's dream had finally come true as he opened his classroom doors.
Output:
Juan