Relatives

Description

Given n, a positive integer, how many positive integers less than n are relatively prime to n? Two integers a and b are relatively prime if there are no integers x > 1, y > 0, z > 0 such that a = xy and b = xz.

Input

There are several test cases. For each test case, standard input contains a line with n <= 1,000,000,000. A line containing 0 follows the last case.

Output

For each test case there should be single line of output answering the question posed above.

Sample Input

7
12
0

Sample Output

6
4

#include<stdio.h>
int phi(int n)
{
    int i,res=n;
    for(i=2;i*i<=n;i++)
    {
        if(n%i==0)
        {
            res=(res/i)*(i-1);
            do
                n/=i;
            while(n%i==0);
        }
    }
    if(n!=1)
           res=(res/n)*(n-1);
    return res;
}
int main()
{
    int n;

    while(~scanf("%d",&n)&&n)
    {
        printf("%d\n",phi(n));
    }
    return 0;
}