#include <iostream>
#include <string>
#include <vector>
#include <cmath>
#include <algorithm>
#include <cstdlib>
#include <ctime>
#include <cstdio>
#include <functional>
#include <set>

using namespace std;


int main()
{	
	int n;
	cin>>n;

	if(n==0) cout<<4<<endl;
	else if(n==1) cout<<3<<endl;
	else printf("%.16f\n",pow(3.0,n)/pow(2.0,(n-1)*2));
	

	return 0;
}