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: Oliver was playing dodgeball at school. Sentence2: Suddenly, a ball smacked him in the face. Sentence3: He fell over and held his nose. Sentence4: When his teacher checked on him they saw that his nose was bleeding. Sentence5: He had to go to the nurse's office.
A:
Nurse, Oliver, Teacher