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