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: Johnny saw the other kids jumping ramps with their bikes. Sentence2: He then attempted to make some jumps himself but crashed each time. Sentence3: Johnny was determined to jump ramps so he practiced every day. Sentence4: He started with small jumps and then graduated to the big ones. Sentence5: Johnny was able to out-jump the best bike jumpers.
Johnny