2014
02-12

# Love you Ten thousand years

Love you Ten thousand years——Earth’s rotation is a day that is the representative of a day I love you. True love, there is no limit and no defects. Earth’s revolution once a year, it is on behalf of my love you more than a year. Permanent horizon, and my heart will never change ……

We say that integer x, 0 < x < n,(n is a odd prime number) is a LovePoint-based-on n if and only if the set { (xi mod n) | 1 <= i <= n-1 } is equal to { 1, …, n-1 }. For example, the powers of 3 modulo 7 are 3, 2, 6, 4, 5, 1, and thus 3 is a LovePoint-based-on 7.
Now give you a integer n >= 3(n will not exceed 231).
We say the number of LovePoint-based-on n is the number of days the earth rotating.
Your task is to calculate the number of days someone loved you.

Each line of the input contains an integer n. Input is terminated by the end-of-file.

Each line of the input contains an integer n. Input is terminated by the end-of-file.

5

2

1. 您没有考虑 树的根节点是负数的情况， 若树的根节点是个很大的负数，那么就要考虑过不过另外一边子树了