
import java.util.Scanner;

public class Main {
    static Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        int k = sc.nextInt();
        int a = sc.nextInt();
        int b = sc.nextInt();

        boolean flag = false;
        for(int i = a; i<=b; i++){
            if(i % k ==0){
                flag = true;
            }
        }

        System.out.println(flag?"OK":"NG");
    }
} import java.util.Scanner; Scanner java.util public class Main {
    static Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        int k = sc.nextInt();
        int a = sc.nextInt();
        int b = sc.nextInt();

        boolean flag = false;
        for(int i = a; i<=b; i++){
            if(i % k ==0){
                flag = true;
            }
        }

        System.out.println(flag?"OK":"NG");
    }
} Main static Scanner sc = new Scanner(System.in); sc new Scanner(System.in) public static void main(String[] args) {
        int k = sc.nextInt();
        int a = sc.nextInt();
        int b = sc.nextInt();

        boolean flag = false;
        for(int i = a; i<=b; i++){
            if(i % k ==0){
                flag = true;
            }
        }

        System.out.println(flag?"OK":"NG");
    } main {
        int k = sc.nextInt();
        int a = sc.nextInt();
        int b = sc.nextInt();

        boolean flag = false;
        for(int i = a; i<=b; i++){
            if(i % k ==0){
                flag = true;
            }
        }

        System.out.println(flag?"OK":"NG");
    } int k = sc.nextInt(); k sc.nextInt() sc.nextInt sc int a = sc.nextInt(); a sc.nextInt() sc.nextInt sc int b = sc.nextInt(); b sc.nextInt() sc.nextInt sc boolean flag = false; flag false for(int i = a; i<=b; i++){
            if(i % k ==0){
                flag = true;
            }
        } int i = a; int i = a; i a i<=b i b i++ i++ i {
            if(i % k ==0){
                flag = true;
            }
        } {
            if(i % k ==0){
                flag = true;
            }
        } if(i % k ==0){
                flag = true;
            } i % k ==0 i % k i k 0 {
                flag = true;
            } flag = true flag true System.out.println(flag?"OK":"NG") System.out.println System.out System System.out flag?"OK":"NG" flag "OK" "NG" String[] args args public class Main {
    static Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        int k = sc.nextInt();
        int a = sc.nextInt();
        int b = sc.nextInt();

        boolean flag = false;
        for(int i = a; i<=b; i++){
            if(i % k ==0){
                flag = true;
            }
        }

        System.out.println(flag?"OK":"NG");
    }
} public class Main {
    static Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        int k = sc.nextInt();
        int a = sc.nextInt();
        int b = sc.nextInt();

        boolean flag = false;
        for(int i = a; i<=b; i++){
            if(i % k ==0){
                flag = true;
            }
        }

        System.out.println(flag?"OK":"NG");
    }
} Main

import java.util.Scanner;

public class Main {
    static Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        int k = sc.nextInt();
        int a = sc.nextInt();
        int b = sc.nextInt();

        boolean flag = false;
        for(int i = a; i<=b; i++){
            if(i % k ==0){
                flag = true;
            }
        }

        System.out.println(flag?"OK":"NG");
    }
}