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: Jill and her brother Jack are both running for Class President. Sentence2: It's a neck and neck race between the two siblings. Sentence3: But Jill narrowly edge out Jack to win. Sentence4: Jack pouts for a week after his sister wins. Sentence5: He finally apologizes for his behavior and congratulates her.
A:
Jill, Jack