In the next video we are going to show how to solve a task using regular expressions. It is not mandatory for you to learn how to use them, but it is an easy way for programmers to find/replace/modify pieces of text really fast.
If you want to spend a few hours learning about RegEx in detail and want to follow a fun interactive tutorial, here is a nice free way to get yourself comfortable with some of the common patterns. Enjoy it! And see you in the next video :) (but it is completely optional!)