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: Dan was 9 and his brother Rob was 5. Sentence2: On Rob's birthday he received a Power Wheels truck. Sentence3: Dan was shocked since he always wanted, but never got one. Sentence4: Dan asked his dad why Rob got one and he didn't. Sentence5: Dan's dad explained Dan was too old for a Power Wheels truck.
Dan, Rob, Dan's dad