#include <bits/stdc++.h>
using namespace std;
int main() {
  int x, a, b;
  cin >> x;
  if (x == 2 || x == 3) {
    cout << x << " " << x;
    a = 0;
  }
  if (x == 1) {
    cout << -1;
  }
  for (a = x / 2; a <= x; a++) {
    for (b = a - 1; b >= 1; b--) {
      if ((a % b == 0) && (a * b > x) && (a / b < x)) {
        cout << a << " " << b;
        b = 0;
        a = x + 1;
      }
    }
  }
}
