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