using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace yukikoda
{
    class Program
    {
        static void Main(string[] args)
        {
            string a = Console.ReadLine();
            string b = Console.ReadLine();

            int aa = 0;
            int bb = 0;
            if (int.TryParse(a,out aa) && int.TryParse(b, out bb))
            {
                Console.WriteLine("NG");
                return;
            }

            if (!a.Equals(aa.ToString()) || !b.Equals(bb.ToString())) {
                Console.WriteLine("NG");
                return;
            }

            if (aa < 0 || aa > 12345 )
            {
                Console.WriteLine("NG");
                return;
            }

            if (bb < 0 || bb > 12345)
            {
                Console.WriteLine("NG");
                return;
            }

            Console.WriteLine("OK");
        }
    }
}