#include <bits/stdc++.h>
using namespace std;
int main() {
  int i, j, k, n, t, x, y, s = 0, c = 0, l;
  cin >> n;
  if (n == 1)
    cout << "-1";
  else
    cout << n - (n - ((n / 2) * 2)) << " " << 2;
}
