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: Ronald was driving down the road. Sentence2: He saw a young boy hitching for a ride. Sentence3: Ronald picked up the boy. Sentence4: He urged the boy to call his parents on his cell phone. Sentence5: Ronald waited at a diner with the boy until his parents arrived.
Ronald, His parents, Young boy