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();
    int c=a%k;
    int d=a+(k-c);
    if(c==0)
    {
      System.out.println("OK");
    }
    else if(b%k==0)
    {
       System.out.println("OK");
    }
    else if(c!=0)
    {
      if(d<=b)
      {
        System.out.println("OK");
      }
      else
      {
         System.out.println("NG");
      }
    }
    else
    {
       System.out.println("NG");
    }
  }
}
     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();
    int c=a%k;
    int d=a+(k-c);
    if(c==0)
    {
      System.out.println("OK");
    }
    else if(b%k==0)
    {
       System.out.println("OK");
    }
    else if(c!=0)
    {
      if(d<=b)
      {
        System.out.println("OK");
      }
      else
      {
         System.out.println("NG");
      }
    }
    else
    {
       System.out.println("NG");
    }
  }
} 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();
    int c=a%k;
    int d=a+(k-c);
    if(c==0)
    {
      System.out.println("OK");
    }
    else if(b%k==0)
    {
       System.out.println("OK");
    }
    else if(c!=0)
    {
      if(d<=b)
      {
        System.out.println("OK");
      }
      else
      {
         System.out.println("NG");
      }
    }
    else
    {
       System.out.println("NG");
    }
  } main {
    Scanner sc=new Scanner(System.in);
    int k=sc.nextInt();
    int a=sc.nextInt();
    int b=sc.nextInt();
    int c=a%k;
    int d=a+(k-c);
    if(c==0)
    {
      System.out.println("OK");
    }
    else if(b%k==0)
    {
       System.out.println("OK");
    }
    else if(c!=0)
    {
      if(d<=b)
      {
        System.out.println("OK");
      }
      else
      {
         System.out.println("NG");
      }
    }
    else
    {
       System.out.println("NG");
    }
  } 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 int c=a%k; c a%k a k int d=a+(k-c); d a+(k-c) a (k-c) k c if(c==0)
    {
      System.out.println("OK");
    }
    else if(b%k==0)
    {
       System.out.println("OK");
    }
    else if(c!=0)
    {
      if(d<=b)
      {
        System.out.println("OK");
      }
      else
      {
         System.out.println("NG");
      }
    }
    else
    {
       System.out.println("NG");
    } c==0 c 0 {
      System.out.println("OK");
    } System.out.println("OK") System.out.println System.out System System.out "OK" if(b%k==0)
    {
       System.out.println("OK");
    }
    else if(c!=0)
    {
      if(d<=b)
      {
        System.out.println("OK");
      }
      else
      {
         System.out.println("NG");
      }
    }
    else
    {
       System.out.println("NG");
    } 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(c!=0)
    {
      if(d<=b)
      {
        System.out.println("OK");
      }
      else
      {
         System.out.println("NG");
      }
    }
    else
    {
       System.out.println("NG");
    } c!=0 c 0 {
      if(d<=b)
      {
        System.out.println("OK");
      }
      else
      {
         System.out.println("NG");
      }
    } if(d<=b)
      {
        System.out.println("OK");
      }
      else
      {
         System.out.println("NG");
      } d<=b d b {
        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" {
       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)
  {
    Scanner sc=new Scanner(System.in);
    int k=sc.nextInt();
    int a=sc.nextInt();
    int b=sc.nextInt();
    int c=a%k;
    int d=a+(k-c);
    if(c==0)
    {
      System.out.println("OK");
    }
    else if(b%k==0)
    {
       System.out.println("OK");
    }
    else if(c!=0)
    {
      if(d<=b)
      {
        System.out.println("OK");
      }
      else
      {
         System.out.println("NG");
      }
    }
    else
    {
       System.out.println("NG");
    }
  }
} 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();
    int c=a%k;
    int d=a+(k-c);
    if(c==0)
    {
      System.out.println("OK");
    }
    else if(b%k==0)
    {
       System.out.println("OK");
    }
    else if(c!=0)
    {
      if(d<=b)
      {
        System.out.println("OK");
      }
      else
      {
         System.out.println("NG");
      }
    }
    else
    {
       System.out.println("NG");
    }
  }
} 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();
    int c=a%k;
    int d=a+(k-c);
    if(c==0)
    {
      System.out.println("OK");
    }
    else if(b%k==0)
    {
       System.out.println("OK");
    }
    else if(c!=0)
    {
      if(d<=b)
      {
        System.out.println("OK");
      }
      else
      {
         System.out.println("NG");
      }
    }
    else
    {
       System.out.println("NG");
    }
  }
}
    