import java.io.*;

public class Main {
    public static void main (String[] args) throws Exception {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        int K = Integer.parseInt (reader.readLine());
        String[] arr = reader.readLine().split (" ");
        int A, B;
        A = Integer.parseInt (arr[0]);
        B = Integer.parseInt (arr[1]);
        System.out.println (A <= B / K * K ? "OK" : "NG");
        return;
    }
} import java.io.*; io.* java public class Main {
    public static void main (String[] args) throws Exception {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        int K = Integer.parseInt (reader.readLine());
        String[] arr = reader.readLine().split (" ");
        int A, B;
        A = Integer.parseInt (arr[0]);
        B = Integer.parseInt (arr[1]);
        System.out.println (A <= B / K * K ? "OK" : "NG");
        return;
    }
} Main public static void main (String[] args) throws Exception {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        int K = Integer.parseInt (reader.readLine());
        String[] arr = reader.readLine().split (" ");
        int A, B;
        A = Integer.parseInt (arr[0]);
        B = Integer.parseInt (arr[1]);
        System.out.println (A <= B / K * K ? "OK" : "NG");
        return;
    } main {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        int K = Integer.parseInt (reader.readLine());
        String[] arr = reader.readLine().split (" ");
        int A, B;
        A = Integer.parseInt (arr[0]);
        B = Integer.parseInt (arr[1]);
        System.out.println (A <= B / K * K ? "OK" : "NG");
        return;
    } BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in)); reader new BufferedReader (new InputStreamReader (System.in)) int K = Integer.parseInt (reader.readLine()); K Integer.parseInt (reader.readLine()) Integer.parseInt Integer reader.readLine() reader.readLine reader String[] arr = reader.readLine().split (" "); arr reader.readLine().split (" ") reader.readLine().split reader.readLine() reader.readLine reader " " int A A B; B A = Integer.parseInt (arr[0]) A Integer.parseInt (arr[0]) Integer.parseInt Integer arr[0] arr 0 B = Integer.parseInt (arr[1]) B Integer.parseInt (arr[1]) Integer.parseInt Integer arr[1] arr 1 System.out.println (A <= B / K * K ? "OK" : "NG") System.out.println System.out System System.out A <= B / K * K ? "OK" : "NG" A <= B / K * K A B / K * K B / K B K K "OK" "NG" return; String[] args args public class Main {
    public static void main (String[] args) throws Exception {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        int K = Integer.parseInt (reader.readLine());
        String[] arr = reader.readLine().split (" ");
        int A, B;
        A = Integer.parseInt (arr[0]);
        B = Integer.parseInt (arr[1]);
        System.out.println (A <= B / K * K ? "OK" : "NG");
        return;
    }
} public class Main {
    public static void main (String[] args) throws Exception {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        int K = Integer.parseInt (reader.readLine());
        String[] arr = reader.readLine().split (" ");
        int A, B;
        A = Integer.parseInt (arr[0]);
        B = Integer.parseInt (arr[1]);
        System.out.println (A <= B / K * K ? "OK" : "NG");
        return;
    }
} Main
import java.io.*;

public class Main {
    public static void main (String[] args) throws Exception {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        int K = Integer.parseInt (reader.readLine());
        String[] arr = reader.readLine().split (" ");
        int A, B;
        A = Integer.parseInt (arr[0]);
        B = Integer.parseInt (arr[1]);
        System.out.println (A <= B / K * K ? "OK" : "NG");
        return;
    }
}