#include <bits/stdc++.h>
using namespace std;
int n, b, c;
int main() {
  cin >> n;
  int a[n][n];
  for (int a = 1; a <= n; a++) {
    for (int b = 1; b <= n; b++) {
      if (a % b == 0 && a * b > n && a / b < n) {
        cout << a << ' ' << b << endl;
        return 0;
      }
    }
  }
  cout << -1;
}
