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: Stanton had been hitting home runs all of his career. Sentence2: Suddenly Stanton could no longer hit home runs. Sentence3: He asked his hitting coach for help. Sentence4: Stanton put an a lot of extra hours with his hitting coach. Sentence5: Stanton started hitting home runs again!
Output:
Hitting coach, Stanton