#include <bits/stdc++.h>
int main() {
  int n, a, b, i, j;
  scanf("%d", &a);
  if (a == 1)
    printf("-1\n");
  else {
    if (a % 2 == 0)
      printf("%d 2\n", a);
    else
      printf("%d 2\n", a - 1);
  }
  return 0;
}
