#include <bits/stdc++.h>
const int INF = 1e9 + 7;
const int MAXA = 1e5 + 10;
const int MOD = 1e9 + 7;
using namespace std;
int x;
int main() {
  cin >> x;
  if (x == 1)
    cout << -1;
  else
    cout << x << " " << x;
  return 0;
}
