[0,1,2,2,3,4,3,4,5,4,6,5,6,5,7,6,8,7,6,8,7,9,8,10, 7,9,8,10,9,11,8,10,12,9,11,10,12,9,11,13,10,12,14, 11,13,10,12,14,11,13,15,12,14,11,16,13,15,12,14, 16,13,15,12,17,14,16,13,18,15,17,14,16,13,18,15, 17,14,19,16]