import java.util.*;
import java.io.*;

public class Main {
    static final int MOD = 1000000007;
    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        try {
            for (int i = 0; i < 2; i++) {
                String a = br.readLine();
                int x = Integer.parseInt(a);
                if (!a.equals(String.valueOf(x)) || x > 12345) {
                    throw new Exception();
                }
            }
            System.out.println("OK");
        } catch(Exception e) {
            System.out.println("NG");
        }
    }
}