using System;

public class Program
{
	public static void Main()
	{
		var A = Console.ReadLine();
		int A_;
		if (int.TryParse(A, out A_))
		{
			if ((A.StartsWith("0") && A_ > 0) || A_ < 0 || 12345 < A_)
			{
				Console.WriteLine("NG");
				return;
			}
		}
		else
		{
			Console.WriteLine("NG");
			return;
		}
		
		var B = Console.ReadLine();
		int B_;
		if (int.TryParse(B, out B_))
		{
			if ((B.StartsWith("0") && B_ > 0) || B_ < 0 || 12345 < B_)
			{
				Console.WriteLine("NG");
				return;
			}
		}
		else
		{
			Console.WriteLine("NG");
			return;
		}
		
		Console.WriteLine("OK");
	}
}