using System;

class Ame
{

	static public void Main(string[] args)
	{
		string A,B;
		A = Console.ReadLine();
		B = Console.ReadLine();
		if(isOK(A) && isOK(B))
			Console.WriteLine("OK");
		else
			Console.WriteLine("NG");
	}

	static bool isOK(string s)
	{

		for(int i=0; i<s.Length; i++)
		{
			if(i==0 && s[i] == '0')
			{
				if(s.Length == 1)
					return true;
				else
					return false;
			}
			if(s[i] >= '0' && s[i] <= '9')
				continue;
			return false;
		}

		int x = int.Parse(s);
		if(x >= 0 && x <= 12345)
			return true;
		else
			return false;
	}
}