I hate the idea of any kind of greatest, because as soon as you start thinking that way, you're not only already wrong, you inescapably narrow your experience of things by trying to make it fit into a hierarchy. Great art has always defied hierarchies by simply existing. What bad irony it is to then do that with great artists such as Chekhov, Beckett, Borges, Cervantes and Kafka, as well as thousands more, and even thousands more we'll never know. It makes no sense.