Problem: Given an integer x, find 2 integers a and b such that: 

  * 1 ≤ a,b ≤ x 
  * b divides a (a is divisible by b). 
  * a ⋅ b>x. 
  * a/b<x. 

Input

The only line contains the integer x (1 ≤ x ≤ 100).

Output

You should output two integers a and b, satisfying the given conditions, separated by a space. If no pair of integers satisfy the conditions above, print "-1" (without quotes).

Examples

Input

10


Output

6 3

Input

1


Output

-1

Solution (in JAVA):

Solution:
    import java.util.Scanner;

    public class Codeforces {
        static int a, b;
        public static void main(String[] args) {
            Scanner scanner = new Scanner(System.in);
            int x = scanner.nextInt();
            if (smartestSearch(x)){
                System.out.println(a+" "+b);
            }else {
                System.out.println(-1);
            }
        }

        /**
         * It's constant time,doesn't get
         * better than this
         * @param x
         * @return
         */
        private static boolean smartestSearch(int x) {
            if (x>1){
                a=x;b=x;
                return true;
            }
            return false;
        }


        /**
         * It's a better search since b has to divide a it
         * means that b<a. Also since a*b > x means we can start at
         * b <- a and stop when a*b <= x for a fixed a.
         *
         * @param x The x for the problem
         * @return A boolean, True if it found a matching pair a,b. False otherwise
         */
        private static boolean betterSearch(int x) {
            for (a = x ; a*2 > x ; a--){
                for (b=a ; a*b > x; b--){
                    if (condition(x)){
                        return true;
                    }
                }
            }
            return false;
        }

        /**
         * This is the brute search, it search absolutely every possible pair that lays
         * in the specified range.
         * @param x
         * @return A boolean, True if it found a matching pair a,b. False otherwise
         */
        static boolean absoluteBruteForce(int x){
            for ( a = 1;a<=x;a++){
                for (b=1 ; b<=x;b++){
                    if (condition(x)){
                        return true;
                    }
                }
            }
            return false;
        }

        private static boolean condition(int x) {
            return a<=x && b<=x && 1 <= a && 1<=b && a%b==0 && a*b >x && a<b*x;
        }


    }