[0,1,2,0,3,1,4,2,5,0,3,6,1,4,7,2,5,8,0,3,6,9,1,4, 7,10,2,5,8,11,0,3,6,9,12,1,4,7,10,13,2,5,8,11,14, 0,3,6,9,12,15,1,4,7,10,13,16,2,5,8,11,14,0,17,3,6, 9,12,15,1,18,4,7,10,13,16,2,19,5,8,11,14,0,17,3, 20,6,9,12,15,1]