[1,2,3,1,4,3,5,4,2,5,1,6,5,7,6,4,7,3,6,2,7,1,8,7, 9,8,6,9,5,8,4,9,3,8,2,9,1,10,9,11,10,8,11,7,10,6, 11,5,10,4,11,3,10,2,11,1,12,11,13,12,10,13,9,12,8, 13,7,12,6,13,5,12,4,13,3,12,2,13,1,14,13,15,14,12, 15,11,14,10]