Ignoring Case in Regex in PHP

By default, in regex, the case of characters matters. In the following example, we will find only lowercase letters:

php<?php
  preg_replace('#[a-z]+#', '!', 'aaa bbb AAA'); // returns '! ! AAA'
?>

We can change this regex behavior by using the modifier i. Let's correct our regex accordingly:

php<?php
  preg_replace('#[a-z]+#i', '!', 'aaa bbb AAA'); // returns '! ! !'
?>

Задание 1

Simplify the following code by using the appropriate modifier:

php<?php
  preg_replace('#[a-zA-Z]+#', '!', 'aaa BBB');
?>