和poj 2409差不多，就是k变成3了，详见
还有不一样的地方是记得特判n==0的情况不然会RE
#include<iostream>
#include<cstdio>
using namespace std;
long long n,ans;
long long ksm(long long a,long long b)
{
long long r=1;
while(b)
{
if(b&1)
r=r*a;
a=a*a;
b>>=1;
}
return r;
}
long long gcd(long long a,long long b)
{
return !b?a:gcd(b,a%b);
}
int main()
{
while(scanf("%lld",&n)&&n!=-1)
{
if(!n)
{
puts("0");
continue;
}
ans=(n&1)?ksm(3,n/2+1)*n:ksm(3,n/2+1)*n/2+ksm(3,n/2)*n/2;
for(int i=1;i<=n;i++)
ans+=ksm(3,gcd(i,n));
printf("%lld\n",ans/2/n);
}
return 0;
}