my bitstream sir as I try to put my original symbol message into a bit stream that a bit stream is as short as possible and race where you could search over all possible binary trees but there would be many many many binaries and then apply decide which one is most efficient but we'll see better schemes than that but you have a very naive way to put is just try all possible binary trees that have the symbols at the leaves and just see for each one of them how long the bitstream is and take the best one we'll see an efficient method