<?php
$regexp = '/д[ ]?[yу][ ]?[рp][ ]?[aа][ ]?[kк]/ui';
$text = "ты Д у р A к";
echo $text;
PD9waHAKCmVycm9yX3JlcG9ydGluZygtMSk7CgokcmVnZXhwID0gJy/QtFsgXT9bedGDXVsgXT9b0YBwXVsgXT9bYdCwXVsgXT9ba9C6XS91aSc7CiR0ZXh0ID0gItGC0Ysg0JQg0YMg0YAgQSDQuiI7CgokdGV4dCA9IHByZWdfcmVwbGFjZSgkcmVnZXhwLCAn0YXQvtGA0L7RiNC40Lkg0YfQtdC70L7QstC10LonLCAkdGV4dCk7CgplY2hvICR0ZXh0Ow==