60pts

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ull unsigned long long
const int N=1e7+5;
ull f[N];

signed main()
{
	int m=3;
	
	f[1]=1ull*m;
	f[2]=1ull*m*(m-1);
	f[3]=1ull*m*(m-1)*(m-2);
	
	for(int i=4;i<N;i++)
	{
		f[i]=1ull*(m-1)*f[i-2]+1ull*(m-2)*f[i-1];		
	} 
	
	int n;
	while(cin>>n)
	{
		cout<<f[n]<<'\n';
	}
	return 0;
}