Little johnny is walking home. he has $300 he has to bring home to his mom. while he is walking a man stops him and gives him a chance to double his money. the man says "i'll give you $600 if you can roll 1 die and get a 4 or above, you can roll 2 dice and get a 5 or 6 on at least one of them, or you can roll 3 dice and get a 6 on at least on die. if you don't i get your $300."

what does johnny do to have the best chance of getting home with the money?