using System;
using System.Collections.Generic;

public class Program
{
	public static void Main()
	{
		var list = new List<string>();
		for (int i = 0; i <= 12345; i++)
		{
			list.Add(i.ToString());
		}
		if (list.Contains(Console.ReadLine())
			&& list.Contains(Console.ReadLine()))
		{
			Console.WriteLine("OK");
		}
		else
		{
			Console.WriteLine("NG");
		}
	}
}