#include <bits/stdc++.h>
int main() {
  int n, a, b, y;
  while (~scanf("%d", &n)) {
    if (n > 1) {
      for (int x = 1; x <= n; x++) {
        for (int y = 1; y <= x; y++) {
          if (x % y == 0 && x * y > n && x / y < n) a = x, b = y;
        }
      }
      printf("%d %d\n", a, b);
    } else
      printf("-1\n");
  }
}
