#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  int x;
  cin >> x;
  if (x == 1)
    cout << -1 << endl;
  else
    cout << x << ' ' << x << endl;
  return 0;
}
