[1,2,2,4,4,5,5,7,7,8,8,10,10,11,11,13,13,14,14,16, 16,17,17,19,19,20,20,22,22,23,23,25,25,26,26,28, 28,29,29,31,31,32,32,34,34,35,35,37,37,38,38,40, 40,41,41,43,43,44,44,46,46,47,47,49,49,50,50]