#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n;
  cin >> n;
  long long ans = 1;
  for (long long i = 1; i <= 5; i++) {
    ans *= n;
    n--;
  }
  cout << (long long)ans * ((ans) / 120);
  return 0;
}
