#include <bits/stdc++.h>
int x(int a) {
  if (a % 2 == 0)
    return a;
  else
    return a - 1;
}
int y(int a) {
  if (a % 2 == 0)
    return a / 2;
  else
    return (a - 1) / 2;
}
int main() {
  int t, a, b;
  scanf("%d", &t);
  if (t == 1) {
    printf("-1");
    return 0;
  } else if (t == 2 || t == 3) {
    printf("%d %d", t, t);
    return 0;
  } else {
    a = x(t);
    b = y(t);
    printf("%d %d", a, b);
  }
}
