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 PYTHON):

Solution:
x = int(raw_input())

def ehab(a):
    b = 2
    if a == 1:
        print(-1)
    else:
        if a % b == 0:
            if a * b > x and a / b < x:
                print a, b
            else:
                ehab(a-1)
        else:
            ehab(a-1)
        
       
ehab(x)