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: Johnny was always told he's very strong for his size. Sentence2: He decided to enter a local tough man competition in his town. Sentence3: The main contest was an arm wrestling competition. Sentence4: Johnny ended up beating his opponent within the first 3 seconds. Sentence5: Johnny was then declared the strongest man in his town.
Output:
Johnny, Opponent