    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;

    public class Main {

        public static void main(String[] args) throws IOException {

            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            int K = Integer.parseInt(br.readLine());
            String [] l = br.readLine().split(" ");
            int A = Integer.parseInt(l[0]);
            int B = Integer.parseInt(l[1]);

            if(A%K == 0 || B%K == 0){
                System.out.println("OK");
            }
            else {
                int x = A/K + 1;
                if((x*K) > B){
                    System.out.println("NG");
                }
                else {
                    System.out.println("OK");
                }
            }
        }
    } import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io public class Main {

        public static void main(String[] args) throws IOException {

            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            int K = Integer.parseInt(br.readLine());
            String [] l = br.readLine().split(" ");
            int A = Integer.parseInt(l[0]);
            int B = Integer.parseInt(l[1]);

            if(A%K == 0 || B%K == 0){
                System.out.println("OK");
            }
            else {
                int x = A/K + 1;
                if((x*K) > B){
                    System.out.println("NG");
                }
                else {
                    System.out.println("OK");
                }
            }
        }
    } Main public static void main(String[] args) throws IOException {

            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            int K = Integer.parseInt(br.readLine());
            String [] l = br.readLine().split(" ");
            int A = Integer.parseInt(l[0]);
            int B = Integer.parseInt(l[1]);

            if(A%K == 0 || B%K == 0){
                System.out.println("OK");
            }
            else {
                int x = A/K + 1;
                if((x*K) > B){
                    System.out.println("NG");
                }
                else {
                    System.out.println("OK");
                }
            }
        } main {

            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            int K = Integer.parseInt(br.readLine());
            String [] l = br.readLine().split(" ");
            int A = Integer.parseInt(l[0]);
            int B = Integer.parseInt(l[1]);

            if(A%K == 0 || B%K == 0){
                System.out.println("OK");
            }
            else {
                int x = A/K + 1;
                if((x*K) > B){
                    System.out.println("NG");
                }
                else {
                    System.out.println("OK");
                }
            }
        } BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) int K = Integer.parseInt(br.readLine()); K Integer.parseInt(br.readLine()) Integer.parseInt Integer br.readLine() br.readLine br String [] l = br.readLine().split(" "); l br.readLine().split(" ") br.readLine().split br.readLine() br.readLine br " " int A = Integer.parseInt(l[0]); A Integer.parseInt(l[0]) Integer.parseInt Integer l[0] l 0 int B = Integer.parseInt(l[1]); B Integer.parseInt(l[1]) Integer.parseInt Integer l[1] l 1 if(A%K == 0 || B%K == 0){
                System.out.println("OK");
            }
            else {
                int x = A/K + 1;
                if((x*K) > B){
                    System.out.println("NG");
                }
                else {
                    System.out.println("OK");
                }
            } A%K == 0 || B%K == 0 A%K == 0 A%K A K 0 B%K == 0 B%K B K 0 {
                System.out.println("OK");
            } System.out.println("OK") System.out.println System.out System System.out "OK" {
                int x = A/K + 1;
                if((x*K) > B){
                    System.out.println("NG");
                }
                else {
                    System.out.println("OK");
                }
            } int x = A/K + 1; x A/K + 1 A/K A K 1 if((x*K) > B){
                    System.out.println("NG");
                }
                else {
                    System.out.println("OK");
                } (x*K) > B (x*K) x K B {
                    System.out.println("NG");
                } System.out.println("NG") System.out.println System.out System System.out "NG" {
                    System.out.println("OK");
                } System.out.println("OK") System.out.println System.out System System.out "OK" String[] args args public class Main {

        public static void main(String[] args) throws IOException {

            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            int K = Integer.parseInt(br.readLine());
            String [] l = br.readLine().split(" ");
            int A = Integer.parseInt(l[0]);
            int B = Integer.parseInt(l[1]);

            if(A%K == 0 || B%K == 0){
                System.out.println("OK");
            }
            else {
                int x = A/K + 1;
                if((x*K) > B){
                    System.out.println("NG");
                }
                else {
                    System.out.println("OK");
                }
            }
        }
    } public class Main {

        public static void main(String[] args) throws IOException {

            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            int K = Integer.parseInt(br.readLine());
            String [] l = br.readLine().split(" ");
            int A = Integer.parseInt(l[0]);
            int B = Integer.parseInt(l[1]);

            if(A%K == 0 || B%K == 0){
                System.out.println("OK");
            }
            else {
                int x = A/K + 1;
                if((x*K) > B){
                    System.out.println("NG");
                }
                else {
                    System.out.println("OK");
                }
            }
        }
    } Main
    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;

    public class Main {

        public static void main(String[] args) throws IOException {

            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            int K = Integer.parseInt(br.readLine());
            String [] l = br.readLine().split(" ");
            int A = Integer.parseInt(l[0]);
            int B = Integer.parseInt(l[1]);

            if(A%K == 0 || B%K == 0){
                System.out.println("OK");
            }
            else {
                int x = A/K + 1;
                if((x*K) > B){
                    System.out.println("NG");
                }
                else {
                    System.out.println("OK");
                }
            }
        }
    }