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

class TEST{
	static void Main(){
		Sol mySol =new Sol();
		mySol.Solve();
	}
}

class Sol{
	public void Solve(){
		
		if(S.Length > 1 && S[0] == '0'){ Console.WriteLine("NG");return;}
		if(T.Length > 1 && T[0] == '0'){ Console.WriteLine("NG");return;}
		int x,y;
		if(!int.TryParse(S,out x) || !int.TryParse(T,out y)){ Console.WriteLine("NG");return;}
		if( x >= 0 && x <= 12345 && y >= 0 && y <= 12345){
			Console.WriteLine("OK");
		}else{
			Console.WriteLine("NG");
		}
		
		
	}
	String S,T;
	public Sol(){
		S= rs();
		T = rs();
	}

	static String rs(){return Console.ReadLine();}
	static int ri(){return int.Parse(Console.ReadLine());}
	static long rl(){return long.Parse(Console.ReadLine());}
	static double rd(){return double.Parse(Console.ReadLine());}
	static String[] rsa(char sep=' '){return Console.ReadLine().Split(sep);}
	static int[] ria(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>int.Parse(e));}
	static long[] rla(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>long.Parse(e));}
	static double[] rda(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>double.Parse(e));}
}