[1,1,2,3,2,3,4,5,3,4,5,6,7,4,5,6,7,8,9,5,6,7,8,9, 10,11,6,7,8,9,10,11,12,13,7,8,9,10,11,12,13,14,15, 8,9,10,11,12,13,14,15,16,17,9,10,11,12,13,14,15, 16,17,18,19,10,11,12,13,14,15,16,17,18,19,20,21, 11,12]