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