import java.util.*;
import java.math.*;

public class Main {
    private static Scanner sc = new Scanner(System.in);
    public static void main(String[] args) throws Exception {
        String a = sc.next();
        String b = sc.next();
        int ai = 0;
        int bi = 0;
        
        try {
            ai = Integer.parseInt(a);
            bi = Integer.parseInt(b);
        } catch (Exception e) {
            System.out.println("NG");
            return;
        }
        
        if ((a.length()!=1&&a.indexOf("0")==0)||(b.length()!=1&&b.indexOf("0")==0)) {
            System.out.println("NG");
            return;
        }
        
        if (ai>12345||bi>12345) {
            System.out.println("NG");
            return;
        }
        
        System.out.println("OK");
    }
}