+506 On planet Enigma, the residents use a currency called the confusion. There are only two confusion bills on Enigma, one worth $7$ confusions and the other worth $12$ confusions. There are also some coins of smaller value, but each weighs over $10$ kilograms, so they are difficult to carry around.
In how many ways can a resident of Enigma use only bills to purchase a toaster that costs 19 confusions?
(Everybody knows, of course, that vendors on Enigma do not give change, so residents must make their purchases with exact change.)
