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