Given the task definition and input, reply with output. 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: John loved hot air balloons. Sentence2: He noticed a flyer advertising a local hot air balloon festival. Sentence3: A few days later he went to the festival. Sentence4: There was probably 100 hot air balloons there! Sentence5: John had a really great time.
John