#include <bits/stdc++.h>
using namespace std;
int main() {
  int x, a, b;
  cin >> x;
  if (x == 1)
    cout << -1 << endl;
  else {
    if (x % 2 == 0)
      cout << x;
    else
      cout << x - 1;
    cout << " ";
    printf("2\n");
  }
}
