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: Billy was in finals week in school. Sentence2: On his first exam, Bill had done exceptionally well. Sentence3: He realized that he had forgotten to study for his next exam. Sentence4: He began panicking on his way to the next test. Sentence5: Billy gave it his best effort anyways.
Billy