[0,1,3,2,4,3,4,3,5,4,5,4,5,4,5,4,6,5,6,5,6,5,6,5, 6,5,6,5,6,5,6,5,7,6,7,6,7,6,7,6,7,6,7,6,7,6,7,6,7, 6,7,6,7,6,7,6,7,6,7,6,7,6,7,6,8,7,8,7,8,7,8,7,8,7, 8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8, 7,8,7,8,7,8]