nyoj 333 mdd的烦恼

#include <iostream>
#include <cstdio>
#include <cstring>

using namespace std;

int Slove_Euler(int n)
{
int i, res;
res = n;
for(i = 2; i*i <= n; ++i)
{
if(n%i == 0)
{
res = res/i*(i-1);
while(n%i == 0)
n /= i;
}
}
if(n != 1)
res = res/n*(n-1);
return res;
}

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