Q: 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: Zack was always worried about getting sick. Sentence2: And he became so worried about the air that he wore a respirator. Sentence3: He wore it during his entire school day. Sentence4: And he told other students that the air quality was terrible. Sentence5: Zack still ended up getting sick and worried much more.
A:
Other students, Zack