[0,1,3,2,4,5,5,6,8,7,9,10,10,11,13,12,14,15,15,16, 18,17,19,20,20,21,23,22,24,25,25,26,28,27,29,30, 30,31,33,32,34,35,35,36,38,37,39,40,40,41]