Class Main
    Public Shared Sub Main()
    Dim K As integer = Console.ReadLine
    dim str() as string = Split(Console.ReadLine())
    if (K = 1) or (Math.Floor(cint(str(0)) / k) <> Math.Floor(cint(str(1)) / K)) then
      Console.WriteLine("OK")
    else
      Console.WriteLine("NG")
    end if
        End Sub
End Class
