import java.util.Scanner;
public class Main
{
  public static void main(String[] args)
  {
    Scanner sc = new Scanner(System.in);
    int x = sc.nextInt();
    int y  = sc.nextInt();
    int z  = sc.nextInt(); 
    boolean b = true;
    for(int i = y; i <= z; i++)
    {
      if(i % x == 0)
        b = false;
    }
    if(b == false)
      System.out.println("OK");
    else
      System.out.println("NG");
  }
} import java.util.Scanner; Scanner java.util public class Main
{
  public static void main(String[] args)
  {
    Scanner sc = new Scanner(System.in);
    int x = sc.nextInt();
    int y  = sc.nextInt();
    int z  = sc.nextInt(); 
    boolean b = true;
    for(int i = y; i <= z; i++)
    {
      if(i % x == 0)
        b = false;
    }
    if(b == false)
      System.out.println("OK");
    else
      System.out.println("NG");
  }
} Main public static void main(String[] args)
  {
    Scanner sc = new Scanner(System.in);
    int x = sc.nextInt();
    int y  = sc.nextInt();
    int z  = sc.nextInt(); 
    boolean b = true;
    for(int i = y; i <= z; i++)
    {
      if(i % x == 0)
        b = false;
    }
    if(b == false)
      System.out.println("OK");
    else
      System.out.println("NG");
  } main {
    Scanner sc = new Scanner(System.in);
    int x = sc.nextInt();
    int y  = sc.nextInt();
    int z  = sc.nextInt(); 
    boolean b = true;
    for(int i = y; i <= z; i++)
    {
      if(i % x == 0)
        b = false;
    }
    if(b == false)
      System.out.println("OK");
    else
      System.out.println("NG");
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int x = sc.nextInt(); x sc.nextInt() sc.nextInt sc int y  = sc.nextInt(); y sc.nextInt() sc.nextInt sc int z  = sc.nextInt(); z sc.nextInt() sc.nextInt sc boolean b = true; b true for(int i = y; i <= z; i++)
    {
      if(i % x == 0)
        b = false;
    } int i = y; int i = y; i y i <= z i z i++ i++ i {
      if(i % x == 0)
        b = false;
    } {
      if(i % x == 0)
        b = false;
    } if(i % x == 0)
        b = false; i % x == 0 i % x i x 0 b = false b false if(b == false)
      System.out.println("OK");
    else
      System.out.println("NG"); b == false b false 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 x = sc.nextInt();
    int y  = sc.nextInt();
    int z  = sc.nextInt(); 
    boolean b = true;
    for(int i = y; i <= z; i++)
    {
      if(i % x == 0)
        b = false;
    }
    if(b == false)
      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 x = sc.nextInt();
    int y  = sc.nextInt();
    int z  = sc.nextInt(); 
    boolean b = true;
    for(int i = y; i <= z; i++)
    {
      if(i % x == 0)
        b = false;
    }
    if(b == false)
      System.out.println("OK");
    else
      System.out.println("NG");
  }
} Main
import java.util.Scanner;
public class Main
{
  public static void main(String[] args)
  {
    Scanner sc = new Scanner(System.in);
    int x = sc.nextInt();
    int y  = sc.nextInt();
    int z  = sc.nextInt(); 
    boolean b = true;
    for(int i = y; i <= z; i++)
    {
      if(i % x == 0)
        b = false;
    }
    if(b == false)
      System.out.println("OK");
    else
      System.out.println("NG");
  }
}
