//https://ncode.syosetu.com/n4830bu/242/
#include <bits/stdc++.h>
using namespace std;

int main() {
    int N;
    cin >> N;
    cout << fixed << setprecision(10) << 12.0 * N / 99 * (N - 1) / 98 * (N - 2) / 97 * (N - 3) / 96 * (N - 4) / 95 << endl;
}