keep repeating this and you can recover the characters that were encoded on so hopefully that convinces do that this is decodable and kind of the point of this is that we actually chose these sets as sub ans of B so that their density in the natural numbers is approximately well it is pretty much the probability of the symbols so you know if you take a lot of natural numbers the fraction of the numbers which Lyoness of a is about one-fourth and the fraction of the numbers that line s of B is about three reports and so this out this encoding