import java.util.Scanner;

public class Main {

    public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);

        int param = scan.nextInt();

        int from = scan.nextInt();
        int to = scan.nextInt();

        boolean is = false;

        for (int i = from; i <= to; i++) {
            if (i % param == 0) {
                is = true;
            }
        }

        if (is) {
            System.out.println("OK");
        } else {
            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 param = scan.nextInt();

        int from = scan.nextInt();
        int to = scan.nextInt();

        boolean is = false;

        for (int i = from; i <= to; i++) {
            if (i % param == 0) {
                is = true;
            }
        }

        if (is) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        }
    }
} Main public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);

        int param = scan.nextInt();

        int from = scan.nextInt();
        int to = scan.nextInt();

        boolean is = false;

        for (int i = from; i <= to; i++) {
            if (i % param == 0) {
                is = true;
            }
        }

        if (is) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        }
    } main {

        Scanner scan = new Scanner(System.in);

        int param = scan.nextInt();

        int from = scan.nextInt();
        int to = scan.nextInt();

        boolean is = false;

        for (int i = from; i <= to; i++) {
            if (i % param == 0) {
                is = true;
            }
        }

        if (is) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        }
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int param = scan.nextInt(); param scan.nextInt() scan.nextInt scan int from = scan.nextInt(); from scan.nextInt() scan.nextInt scan int to = scan.nextInt(); to scan.nextInt() scan.nextInt scan boolean is = false; is false for (int i = from; i <= to; i++) {
            if (i % param == 0) {
                is = true;
            }
        } int i = from; int i = from; i from i <= to i to i++ i++ i {
            if (i % param == 0) {
                is = true;
            }
        } {
            if (i % param == 0) {
                is = true;
            }
        } if (i % param == 0) {
                is = true;
            } i % param == 0 i % param i param 0 {
                is = true;
            } is = true is true if (is) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        } is {
            System.out.println("OK");
        } System.out.println("OK") System.out.println System.out System System.out "OK" {
            System.out.println("NG");
        } 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 param = scan.nextInt();

        int from = scan.nextInt();
        int to = scan.nextInt();

        boolean is = false;

        for (int i = from; i <= to; i++) {
            if (i % param == 0) {
                is = true;
            }
        }

        if (is) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        }
    }
} public class Main {

    public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);

        int param = scan.nextInt();

        int from = scan.nextInt();
        int to = scan.nextInt();

        boolean is = false;

        for (int i = from; i <= to; i++) {
            if (i % param == 0) {
                is = true;
            }
        }

        if (is) {
            System.out.println("OK");
        } else {
            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 param = scan.nextInt();

        int from = scan.nextInt();
        int to = scan.nextInt();

        boolean is = false;

        for (int i = from; i <= to; i++) {
            if (i % param == 0) {
                is = true;
            }
        }

        if (is) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        }
    }
}
