#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define REP(i,n) for(ll i=0; i<(n); ++i)

int main() {
	cout << fixed << setprecision(10);
	ll n; cin >> n;

	ll p_3 = 1, p_4 = 1;
	REP(i, n) { p_3 *= 3; p_4 *= 4; }

	cout << p_3 * 4 / (double)p_4 << endl;

	return 0;
}