#include <bits/stdc++.h>
using namespace std;
long long n, i, j, k, l, m, a, b, c, p[1010];
string s;
int main() {
  cin >> n;
  if (n == 1) {
    cout << -1;
    return 0;
  } else {
    cout << n << " " << n;
  }
}
