#!/usr/bin/env python3
a = input()
b = input()
result = 'NG'
if a.isdigit() and b.isdigit():
    if  (a == str(int(a)) and 0 <= int(a) <= 12345) and( b == str(int(b)) and 0 <= int(b) <= 12345):
        result = 'OK'
    
    
    
print(result)