
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int k = Integer.parseInt(scan.next());
        int a = Integer.parseInt(scan.next());
        int b = Integer.parseInt(scan.next());
        scan.close();

        for (int i = a; i <= b; i++) {
            if (i % k == 0) {
                System.out.println("OK");
                return;
            }
        }
        System.out.println("NG");
    }
} import java.util.Scanner; Scanner java.util public class Main {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int k = Integer.parseInt(scan.next());
        int a = Integer.parseInt(scan.next());
        int b = Integer.parseInt(scan.next());
        scan.close();

        for (int i = a; i <= b; i++) {
            if (i % k == 0) {
                System.out.println("OK");
                return;
            }
        }
        System.out.println("NG");
    }
} Main public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int k = Integer.parseInt(scan.next());
        int a = Integer.parseInt(scan.next());
        int b = Integer.parseInt(scan.next());
        scan.close();

        for (int i = a; i <= b; i++) {
            if (i % k == 0) {
                System.out.println("OK");
                return;
            }
        }
        System.out.println("NG");
    } main {
        Scanner scan = new Scanner(System.in);
        int k = Integer.parseInt(scan.next());
        int a = Integer.parseInt(scan.next());
        int b = Integer.parseInt(scan.next());
        scan.close();

        for (int i = a; i <= b; i++) {
            if (i % k == 0) {
                System.out.println("OK");
                return;
            }
        }
        System.out.println("NG");
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int k = Integer.parseInt(scan.next()); k Integer.parseInt(scan.next()) Integer.parseInt Integer scan.next() scan.next scan int a = Integer.parseInt(scan.next()); a Integer.parseInt(scan.next()) Integer.parseInt Integer scan.next() scan.next scan int b = Integer.parseInt(scan.next()); b Integer.parseInt(scan.next()) Integer.parseInt Integer scan.next() scan.next scan scan.close() scan.close scan for (int i = a; i <= b; i++) {
            if (i % k == 0) {
                System.out.println("OK");
                return;
            }
        } int i = a; int i = a; i a i <= b i b i++ i++ i {
            if (i % k == 0) {
                System.out.println("OK");
                return;
            }
        } {
            if (i % k == 0) {
                System.out.println("OK");
                return;
            }
        } if (i % k == 0) {
                System.out.println("OK");
                return;
            } i % k == 0 i % k i k 0 {
                System.out.println("OK");
                return;
            } System.out.println("OK") System.out.println System.out System System.out "OK" return; System.out.println("NG") System.out.println System.out System System.out "NG" String[] args args public class Main {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int k = Integer.parseInt(scan.next());
        int a = Integer.parseInt(scan.next());
        int b = Integer.parseInt(scan.next());
        scan.close();

        for (int i = a; i <= b; i++) {
            if (i % k == 0) {
                System.out.println("OK");
                return;
            }
        }
        System.out.println("NG");
    }
} public class Main {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int k = Integer.parseInt(scan.next());
        int a = Integer.parseInt(scan.next());
        int b = Integer.parseInt(scan.next());
        scan.close();

        for (int i = a; i <= b; i++) {
            if (i % k == 0) {
                System.out.println("OK");
                return;
            }
        }
        System.out.println("NG");
    }
} Main

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int k = Integer.parseInt(scan.next());
        int a = Integer.parseInt(scan.next());
        int b = Integer.parseInt(scan.next());
        scan.close();

        for (int i = a; i <= b; i++) {
            if (i % k == 0) {
                System.out.println("OK");
                return;
            }
        }
        System.out.println("NG");
    }
}