#include <bits/stdc++.h>
using namespace std;
int main() {
  long long p = 1, n;
  cin >> n;
  p = n * (n - 1) * (n - 2) * (n - 3) * (n - 4);
  p *= n * (n - 1) * (n - 2) * (n - 3) * (n - 4) / 2 / 3 / 4 / 5;
  cout << p;
  return 0;
}
