1, 2, 4, 3, 8, 9, 10, 5, 7, 14, 11, 6, 12, 13, 15, 18, 17, 16, 20, 19, 22, 24, 23, 21, 27, 25, 33, 35, 28, 29, 26, 30, 31, 32, 34, 37, 36, 38, 41, 40, 42, 43, 39, 45, 44, 46, 47, 48, 50, 49, 52, 54, 53, 51, 57, 55, 63, 56, 59, 58, 60, 61, 62, 64, 65, 66, 68