#include <iostream>
#include <cstdio>

using namespace std;

int main() {
	int n;

	cin >> n;
	if (n < 5) {
		cout << 0 << endl;
		return 0;
	}

	double ans = 1.0 * n * (n - 1) * (n - 2) * (n - 3) * (n - 4) / 99 / 98 / 97 / 96 / 95;
	ans *= 12;

	printf("%.9f\n", ans);
	return 0;
}