POJ2407(欧拉函数)

#include <cstdio>
using namespace std;
int euler(int n)
{
    int ret=n;
    for(int i=2;i*i<=n;i++)
    {
        if(n%i==0)
        {
            ret=ret-ret/i;
            while(n%i==0)    n/=i;
                
        }
    }
    if(n>1)    ret=ret-ret/n;
    return ret;
}
int main()
{
    int n;
    while(scanf("%d",&n)!=EOF&&n!=0)
    {
        int res=euler(n);
        printf("%d\n",res);
    }
    return 0;
}