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: My wife hates her job. Sentence2: She is a teacher to sixth graders and she always gets headaches. Sentence3: She complains that they are way to loud and don't listen. Sentence4: She asked the principal if she could teach at the high school level. Sentence5: The principal allowed her to switch to the junior year, she's happy.
I (myself), School, Principal, Sixth graders, Wife