    import java.util.*;
     
    public class Main{
          public static void main(String[] args) {
                Scanner sc = new Scanner(System.in);
                int k = sc.nextInt();
                int a = sc.nextInt();
                int b = sc.nextInt();
                for(; a <= b+1; a++){
                  if(a % k == 0){
                    System.out.println("OK");
                    break;
                  } else if(a == b){
                    System.out.println("NG");
                    break;
                  }
                }
              }
    } import java.util.*; util.* java public class Main{
          public static void main(String[] args) {
                Scanner sc = new Scanner(System.in);
                int k = sc.nextInt();
                int a = sc.nextInt();
                int b = sc.nextInt();
                for(; a <= b+1; a++){
                  if(a % k == 0){
                    System.out.println("OK");
                    break;
                  } else if(a == b){
                    System.out.println("NG");
                    break;
                  }
                }
              }
    } Main public static void main(String[] args) {
                Scanner sc = new Scanner(System.in);
                int k = sc.nextInt();
                int a = sc.nextInt();
                int b = sc.nextInt();
                for(; a <= b+1; a++){
                  if(a % k == 0){
                    System.out.println("OK");
                    break;
                  } else if(a == b){
                    System.out.println("NG");
                    break;
                  }
                }
              } main {
                Scanner sc = new Scanner(System.in);
                int k = sc.nextInt();
                int a = sc.nextInt();
                int b = sc.nextInt();
                for(; a <= b+1; a++){
                  if(a % k == 0){
                    System.out.println("OK");
                    break;
                  } else if(a == b){
                    System.out.println("NG");
                    break;
                  }
                }
              } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int k = sc.nextInt(); k sc.nextInt() sc.nextInt sc int a = sc.nextInt(); a sc.nextInt() sc.nextInt sc int b = sc.nextInt(); b sc.nextInt() sc.nextInt sc for(; a <= b+1; a++){
                  if(a % k == 0){
                    System.out.println("OK");
                    break;
                  } else if(a == b){
                    System.out.println("NG");
                    break;
                  }
                } ; a <= b+1 a b+1 b 1 a++ a++ a {
                  if(a % k == 0){
                    System.out.println("OK");
                    break;
                  } else if(a == b){
                    System.out.println("NG");
                    break;
                  }
                } {
                  if(a % k == 0){
                    System.out.println("OK");
                    break;
                  } else if(a == b){
                    System.out.println("NG");
                    break;
                  }
                } if(a % k == 0){
                    System.out.println("OK");
                    break;
                  } else if(a == b){
                    System.out.println("NG");
                    break;
                  } a % k == 0 a % k a k 0 {
                    System.out.println("OK");
                    break;
                  } System.out.println("OK") System.out.println System.out System System.out "OK" break; if(a == b){
                    System.out.println("NG");
                    break;
                  } a == b a b {
                    System.out.println("NG");
                    break;
                  } System.out.println("NG") System.out.println System.out System System.out "NG" break; String[] args args public class Main{
          public static void main(String[] args) {
                Scanner sc = new Scanner(System.in);
                int k = sc.nextInt();
                int a = sc.nextInt();
                int b = sc.nextInt();
                for(; a <= b+1; a++){
                  if(a % k == 0){
                    System.out.println("OK");
                    break;
                  } else if(a == b){
                    System.out.println("NG");
                    break;
                  }
                }
              }
    } public class Main{
          public static void main(String[] args) {
                Scanner sc = new Scanner(System.in);
                int k = sc.nextInt();
                int a = sc.nextInt();
                int b = sc.nextInt();
                for(; a <= b+1; a++){
                  if(a % k == 0){
                    System.out.println("OK");
                    break;
                  } else if(a == b){
                    System.out.println("NG");
                    break;
                  }
                }
              }
    } Main
    import java.util.*;
     
    public class Main{
          public static void main(String[] args) {
                Scanner sc = new Scanner(System.in);
                int k = sc.nextInt();
                int a = sc.nextInt();
                int b = sc.nextInt();
                for(; a <= b+1; a++){
                  if(a % k == 0){
                    System.out.println("OK");
                    break;
                  } else if(a == b){
                    System.out.println("NG");
                    break;
                  }
                }
              }
    }