hdu-1163-Eddy's digital Roots

#include<cstdio>
#include<iostream>
using namespace std;
int main()
{
    int n,sum,i;
    while(cin>>n&&n)
    {
        for(sum=1,i=0;i<n;i++)
            sum=sum*n%9;
        cout<<(sum==0?9:sum)<<endl;
    }
    return 0;
}