[0,1,2,1,2,3,2,3,2,3,2,3,4,3,4,3,4,3,4,3,4,5,4,5, 4,5,4,5,4,5,4,5,6,5,6,5,6,5,6,5,6,5,6,5,6,7,6,7,6, 7,6,7,6,7,6,7,6,7,6,7,6,7,8,7,8,7,8,7,8,7,8,7,8,7, 8,7,8,7,8,9,8,9]