
import java.util.*;
import java.io.*;
public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int count = 0;
        for(int i = b; i<=c;i++){
            if(i%a==0){
               count++;
               break;
            }
            else{
                continue;
            }
        }
        if(count>0) System.out.println("OK");
        else System.out.println("NG");
    }
} import java.util.*; util.* java import java.io.*; io.* java public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int count = 0;
        for(int i = b; i<=c;i++){
            if(i%a==0){
               count++;
               break;
            }
            else{
                continue;
            }
        }
        if(count>0) System.out.println("OK");
        else System.out.println("NG");
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int count = 0;
        for(int i = b; i<=c;i++){
            if(i%a==0){
               count++;
               break;
            }
            else{
                continue;
            }
        }
        if(count>0) System.out.println("OK");
        else System.out.println("NG");
    } main {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int count = 0;
        for(int i = b; i<=c;i++){
            if(i%a==0){
               count++;
               break;
            }
            else{
                continue;
            }
        }
        if(count>0) System.out.println("OK");
        else System.out.println("NG");
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int a = sc.nextInt(); a sc.nextInt() sc.nextInt sc int b = sc.nextInt(); b sc.nextInt() sc.nextInt sc int c = sc.nextInt(); c sc.nextInt() sc.nextInt sc int count = 0; count 0 for(int i = b; i<=c;i++){
            if(i%a==0){
               count++;
               break;
            }
            else{
                continue;
            }
        } int i = b; int i = b; i b i<=c i c i++ i++ i {
            if(i%a==0){
               count++;
               break;
            }
            else{
                continue;
            }
        } {
            if(i%a==0){
               count++;
               break;
            }
            else{
                continue;
            }
        } if(i%a==0){
               count++;
               break;
            }
            else{
                continue;
            } i%a==0 i%a i a 0 {
               count++;
               break;
            } count++ count break; {
                continue;
            } continue; if(count>0) System.out.println("OK");
        else System.out.println("NG"); count>0 count 0 System.out.println("OK") System.out.println System.out System System.out "OK" 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 sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int count = 0;
        for(int i = b; i<=c;i++){
            if(i%a==0){
               count++;
               break;
            }
            else{
                continue;
            }
        }
        if(count>0) System.out.println("OK");
        else System.out.println("NG");
    }
} public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int count = 0;
        for(int i = b; i<=c;i++){
            if(i%a==0){
               count++;
               break;
            }
            else{
                continue;
            }
        }
        if(count>0) System.out.println("OK");
        else System.out.println("NG");
    }
} Main

import java.util.*;
import java.io.*;
public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int count = 0;
        for(int i = b; i<=c;i++){
            if(i%a==0){
               count++;
               break;
            }
            else{
                continue;
            }
        }
        if(count>0) System.out.println("OK");
        else System.out.println("NG");
    }
}
