12 -> 1 + 2 + 3 + 4 + 6 = 16 16 -> 1 + 2 + 4 + 8 = 15 15 -> 1 + 3 + 5 = 9 9-> 1 + 3 = 4 4-> 1 + 2 = 3 3-> 1 = 1
无
一个整数