1, 4, 2, 6, 3, 8, 5, 9, 7, 12, 10, 14, 16, 11, 18, 13, 20, 15, 21, 24, 17, 25, 19, 27, 22, 26, 28, 23, 32, 29, 36, 30, 33, 39, 40, 31, 44, 34, 38, 42, 35, 45, 37, 48, 41, 49, 43, 50, 46, 52, 47, 54, 51, 56, 53, 60, 55, 63, 57, 64, 58, 62, 66, 68, 59, 72, 61