import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner in = new Scanner(System.in);
        int x = in.nextInt(), n = in.nextInt(), m = in.nextInt();
        if (x * (m / x) >= n) {
            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) {
        // TODO Auto-generated method stub
        Scanner in = new Scanner(System.in);
        int x = in.nextInt(), n = in.nextInt(), m = in.nextInt();
        if (x * (m / x) >= n) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        }
    }

} Main public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner in = new Scanner(System.in);
        int x = in.nextInt(), n = in.nextInt(), m = in.nextInt();
        if (x * (m / x) >= n) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        }
    } main {
        // TODO Auto-generated method stub
        Scanner in = new Scanner(System.in);
        int x = in.nextInt(), n = in.nextInt(), m = in.nextInt();
        if (x * (m / x) >= n) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        }
    } Scanner in = new Scanner(System.in); in new Scanner(System.in) int x = in.nextInt() x in.nextInt() in.nextInt in n = in.nextInt() n in.nextInt() in.nextInt in m = in.nextInt(); m in.nextInt() in.nextInt in if (x * (m / x) >= n) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        } x * (m / x) >= n x * (m / x) x (m / x) m x n {
            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) {
        // TODO Auto-generated method stub
        Scanner in = new Scanner(System.in);
        int x = in.nextInt(), n = in.nextInt(), m = in.nextInt();
        if (x * (m / x) >= n) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        }
    }

} public class Main {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner in = new Scanner(System.in);
        int x = in.nextInt(), n = in.nextInt(), m = in.nextInt();
        if (x * (m / x) >= n) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        }
    }

} Main
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner in = new Scanner(System.in);
        int x = in.nextInt(), n = in.nextInt(), m = in.nextInt();
        if (x * (m / x) >= n) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        }
    }

}
