Instructions: 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.
Input: Sentence1: Josh was the best speller in his class. Sentence2: He could spell any word. Sentence3: His school was having a spelling bee. Sentence4: He was invited to compete. Sentence5: When it was his turn, he won!
Output:
School, Josh