hdu2085 核反应堆

#include<stdio.h>
int main()
{
    int i,n;
    __int64 high,low,k;
    while(scanf("%d",&n),n+1)
    {
        for(high=1,low=i=0;i<n;++i)
        {
            k=high;
            high=3*high+2*low;
            low=k+low;
        }
        printf("%I64d, %I64d\n",high,low);
    }
    return 0;
}