#include <bits/stdc++.h>
using namespace std;
long long permutation(long long, long long);
int main(int argc, const char* argv[]) {
  long long n;
  scanf("%lld", &n);
  printf("%lld\n", permutation(n, 5) / 120 * permutation(n, 5));
  return 0;
}
long long permutation(long long n, long long r) {
  return (r == 1) ? n : (permutation(n - 1, r - 1) * n);
}
