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.
Q: Sentence1: Mary needed to improve her math skills. Sentence2: She contacted the campus tutoring office and asked for help. Sentence3: A tutor came to Mary's dorm and offered to assist her. Sentence4: Mary worked very hard with the tutor for several weeks. Sentence5: Mary aced her math final exam!
A:
Tutor, Mary, Campus tutoring office