import static java.lang.System.out;
import java.util.Scanner;

public class No446{
	public static void main(String[] args){
		Scanner sc=new Scanner(System.in);
		String A=sc.nextLine();
		String B=sc.nextLine();
		int a=check(A);
		int b=check(B);
		if(a==1&&b==1){
			out.println("OK");
		}else{
			out.println("NG");
		}
	}
	private static int check(String s){
		if(s.length()<1&&s.length()>5){return 0;}
		if(s.length()>1&&s.indexOf("0")==0){return 0;}
		try{int n=Integer.parseInt(s);
			if(n<=12345){return 1;}
			else{return 0;}
		}catch(Exception e){return 0;}
	}
}