using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using System.Numerics;




namespace contest
{

    class contest
    {


        static void Main(string[] args)
        {


            //int n = int.Parse(Console.ReadLine());
            //var input = Console.ReadLine().Split().Select(int.Parse).ToArray();

            //var num = Console.ReadLine().Split().Select(int.Parse).ToArray();




            string A = (Console.ReadLine());
            string B = (Console.ReadLine());



            if(A.Any(c=>c<'0' || c>'9')|| B.Any(c => c < '0' || c > '9'))
            {
                Console.WriteLine("NG");
            }
            else if((A.Length>1 && A[0]=='0') || (B.Length>1 && B[0]=='0'))
            {
                Console.WriteLine("NG");
            }
            else if (int.Parse(A)>12345 || int.Parse(B)>12345)
            {
                Console.WriteLine("NG");
            }
            else
            {
                Console.WriteLine("OK");
            }



           


        }

       

    }


}