Online PHP editor | output for gLuYe

<?php $Distances = array( "Berlin" => array("Berlin" => 0, "Moscow" => 1607.99, "Paris" => 876.96, "Prague" => 280.34, "Rome" => 1181.67), "Moscow" => array("Berlin" => 1607.99, "Moscow" => 0, "Paris" => 2484.92, "Prague" => 1664.04, "Rome" => 2374.26), "Paris" => array("Berlin" => 876.96, "Moscow" => 641.31, "Paris" => 0, "Prague" => 885.38, "Rome" => 1105.76), "Prague" => array("Berlin" => 280.34, "Moscow" => 1664.04, "Paris" => 885.38, "Prague" => 0, "Rome" => 922), "Rome" => array("Berlin" => 1181.67, "Moscow" => 2374.26, "Paris" => 1105.76, "Prague" => 922, "Rome" => 0) ); $_POST = array('start' => 'Paris', 'end' => 'Berlin'); echo $Distances[$_POST['start']][$_POST['end']] ?? 'Unknown'; if (isset($_POST['start'], $_POST['end'], $Distances[$_POST['start']][$_POST['end']])) { echo $Distances[$_POST['start']][$_POST['end']]; } else { echo "Unknown"; }