#include <bits/stdc++.h>
using namespace std;
int main() {
  int y;
  cin >> y;
  if (y == 1) {
    cout << "-1" << endl;
    return 0;
  } else if (y % 2 == 0) {
    cout << y << " " << y << endl;
    return 0;
  } else {
    cout << y - 1 << " " << y - 1 << endl;
    return 0;
  }
}
