#include <bits/stdc++.h>
using namespace std;
using i64 = int64_t;
using vi = vector<i64>;
using vvi = vector<vi>;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    cout.setf(ios::fixed);
    cout.precision(10);
    int n;
    cin >> n;
    cout << pow(3.0 / 4.0, n) * 4 << endl;
}