#include <bits/stdc++.h>
using namespace std;

int main() {
    int n;
    cin >> n;
    double ans;
    if (n == 0) {
        ans = 4;
    } else if (n == 1) {
        ans = 3;
    } else {
        ans = pow(3.0 / 4.0, n) * 4.0;
    }
    cout << fixed << setprecision(15) << ans << '\n';
}