[1,0,0,2,2,1,1,3,3,2,2,4,4,3,3,5,5,4,4,6,6,5,5,7, 7,6,6,8,8,7,7,9,9,8,8,10,10,9,9,11,11,10,10,12,12, 11,11,13,13,12,12,14,14,13,13,15,15,14,14,16,16, 15,15,17,17,16,16,18,18,17,17,19,19,18,18,20,20, 19,19,21,21,20]