import java.util.*;
public class Main{
    public static void main(String[] args) {
        int test;
        Scanner sc=new Scanner(System.in);
        //test=sc.nextInt();
     //   while(test-->0){
            int k;
            int a,b;
            k= sc.nextInt();
            a=sc.nextInt();
            b=sc.nextInt();
            if(a%k==0|| b%k==0){
                System.out.println("OK");
            }
            else {
                if((a/k)<(b/k)){
                    System.out.println("OK");
                }
                else{
                    System.out.println("NG");
                }
            }

       // }
    }
} import java.util.*; util.* java public class Main{
    public static void main(String[] args) {
        int test;
        Scanner sc=new Scanner(System.in);
        //test=sc.nextInt();
     //   while(test-->0){
            int k;
            int a,b;
            k= sc.nextInt();
            a=sc.nextInt();
            b=sc.nextInt();
            if(a%k==0|| b%k==0){
                System.out.println("OK");
            }
            else {
                if((a/k)<(b/k)){
                    System.out.println("OK");
                }
                else{
                    System.out.println("NG");
                }
            }

       // }
    }
} Main public static void main(String[] args) {
        int test;
        Scanner sc=new Scanner(System.in);
        //test=sc.nextInt();
     //   while(test-->0){
            int k;
            int a,b;
            k= sc.nextInt();
            a=sc.nextInt();
            b=sc.nextInt();
            if(a%k==0|| b%k==0){
                System.out.println("OK");
            }
            else {
                if((a/k)<(b/k)){
                    System.out.println("OK");
                }
                else{
                    System.out.println("NG");
                }
            }

       // }
    } main {
        int test;
        Scanner sc=new Scanner(System.in);
        //test=sc.nextInt();
     //   while(test-->0){
            int k;
            int a,b;
            k= sc.nextInt();
            a=sc.nextInt();
            b=sc.nextInt();
            if(a%k==0|| b%k==0){
                System.out.println("OK");
            }
            else {
                if((a/k)<(b/k)){
                    System.out.println("OK");
                }
                else{
                    System.out.println("NG");
                }
            }

       // }
    } int test; test Scanner sc=new Scanner(System.in); sc new Scanner(System.in) int k; k int a a b; b k= sc.nextInt() k sc.nextInt() sc.nextInt sc a=sc.nextInt() a sc.nextInt() sc.nextInt sc b=sc.nextInt() b sc.nextInt() sc.nextInt sc if(a%k==0|| b%k==0){
                System.out.println("OK");
            }
            else {
                if((a/k)<(b/k)){
                    System.out.println("OK");
                }
                else{
                    System.out.println("NG");
                }
            } a%k==0|| b%k==0 a%k==0 a%k a k 0 b%k==0 b%k b k 0 {
                System.out.println("OK");
            } System.out.println("OK") System.out.println System.out System System.out "OK" {
                if((a/k)<(b/k)){
                    System.out.println("OK");
                }
                else{
                    System.out.println("NG");
                }
            } if((a/k)<(b/k)){
                    System.out.println("OK");
                }
                else{
                    System.out.println("NG");
                } (a/k)<(b/k) (a/k) a k (b/k) b k {
                    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) {
        int test;
        Scanner sc=new Scanner(System.in);
        //test=sc.nextInt();
     //   while(test-->0){
            int k;
            int a,b;
            k= sc.nextInt();
            a=sc.nextInt();
            b=sc.nextInt();
            if(a%k==0|| b%k==0){
                System.out.println("OK");
            }
            else {
                if((a/k)<(b/k)){
                    System.out.println("OK");
                }
                else{
                    System.out.println("NG");
                }
            }

       // }
    }
} public class Main{
    public static void main(String[] args) {
        int test;
        Scanner sc=new Scanner(System.in);
        //test=sc.nextInt();
     //   while(test-->0){
            int k;
            int a,b;
            k= sc.nextInt();
            a=sc.nextInt();
            b=sc.nextInt();
            if(a%k==0|| b%k==0){
                System.out.println("OK");
            }
            else {
                if((a/k)<(b/k)){
                    System.out.println("OK");
                }
                else{
                    System.out.println("NG");
                }
            }

       // }
    }
} Main
import java.util.*;
public class Main{
    public static void main(String[] args) {
        int test;
        Scanner sc=new Scanner(System.in);
        //test=sc.nextInt();
     //   while(test-->0){
            int k;
            int a,b;
            k= sc.nextInt();
            a=sc.nextInt();
            b=sc.nextInt();
            if(a%k==0|| b%k==0){
                System.out.println("OK");
            }
            else {
                if((a/k)<(b/k)){
                    System.out.println("OK");
                }
                else{
                    System.out.println("NG");
                }
            }

       // }
    }
}