<?php
   $cadena = "KTALINA";
   $t = strlen($cadena);
   $r = $t / 2;
   $rsd = round($r,PHP_ROUND_HALF_DOWN);
   $rsu = round($r,PHP_ROUND_HALF_UP);
   $text_1 = substr($cadena,-$t, -$rsd);
   $text_2 = substr($cadena, -$rsu, $t);
?>