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