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

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

        if (Judge(a, b))
        {
            Console.WriteLine("OK");
        }
        else
        {
            Console.WriteLine("NG");
        }

        Console.Read();
    }

    static bool Judge(string a, string b)
    {
        int i;
        string n = a;
        string m = b;

        if (!int.TryParse(a, out i) || !int.TryParse(b, out i))
        {
            return false;
        }

        if (a != "0")
        {
            n = a.TrimStart('0');
        }
        if (b != "0")
        {
            m = b.TrimStart('0');
        }

        if (a != n || b != m)
        {
            return false;
        }

        if (int.Parse(a) > 12345 || int.Parse(b) > 12345)
        {
            return false;
        }

        return true;
    }
}