import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner s1 = new Scanner(System.in);
        int n = s1.nextInt();
        int A = s1.nextInt();
        int B = s1.nextInt();
        for(int i = A; i <= B; i++) {
            if(i % n == 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 s1 = new Scanner(System.in);
        int n = s1.nextInt();
        int A = s1.nextInt();
        int B = s1.nextInt();
        for(int i = A; i <= B; i++) {
            if(i % n == 0) {
                System.out.println("OK");
                return;
            }
        }
        System.out.println("NG");
    }
} Main public static void main(String[] args) {
        Scanner s1 = new Scanner(System.in);
        int n = s1.nextInt();
        int A = s1.nextInt();
        int B = s1.nextInt();
        for(int i = A; i <= B; i++) {
            if(i % n == 0) {
                System.out.println("OK");
                return;
            }
        }
        System.out.println("NG");
    } main {
        Scanner s1 = new Scanner(System.in);
        int n = s1.nextInt();
        int A = s1.nextInt();
        int B = s1.nextInt();
        for(int i = A; i <= B; i++) {
            if(i % n == 0) {
                System.out.println("OK");
                return;
            }
        }
        System.out.println("NG");
    } Scanner s1 = new Scanner(System.in); s1 new Scanner(System.in) int n = s1.nextInt(); n s1.nextInt() s1.nextInt s1 int A = s1.nextInt(); A s1.nextInt() s1.nextInt s1 int B = s1.nextInt(); B s1.nextInt() s1.nextInt s1 for(int i = A; i <= B; i++) {
            if(i % n == 0) {
                System.out.println("OK");
                return;
            }
        } int i = A; int i = A; i A i <= B i B i++ i++ i {
            if(i % n == 0) {
                System.out.println("OK");
                return;
            }
        } {
            if(i % n == 0) {
                System.out.println("OK");
                return;
            }
        } if(i % n == 0) {
                System.out.println("OK");
                return;
            } i % n == 0 i % n i n 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 s1 = new Scanner(System.in);
        int n = s1.nextInt();
        int A = s1.nextInt();
        int B = s1.nextInt();
        for(int i = A; i <= B; i++) {
            if(i % n == 0) {
                System.out.println("OK");
                return;
            }
        }
        System.out.println("NG");
    }
} public class Main {

    public static void main(String[] args) {
        Scanner s1 = new Scanner(System.in);
        int n = s1.nextInt();
        int A = s1.nextInt();
        int B = s1.nextInt();
        for(int i = A; i <= B; i++) {
            if(i % n == 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 s1 = new Scanner(System.in);
        int n = s1.nextInt();
        int A = s1.nextInt();
        int B = s1.nextInt();
        for(int i = A; i <= B; i++) {
            if(i % n == 0) {
                System.out.println("OK");
                return;
            }
        }
        System.out.println("NG");
    }
}
