You can think of character classes as characters with special meaning. They are recognized as special when you place the \ before the character.
Here are a list of the characters classes in JavaScript:
., \cX, \d, \D, \f, \n, \r, \s, \S, \t, \v, \w, \W, \0, \xhh, \uhhhh, \uhhhhh,
You might get text that looks like it's all English characters but it very well may not be:
pànts !== pants
To ensure that you only get the characters you want in a string you will need to use the character classes that accept hexadecimal digits.
Create a regex that matches the word "innokodakademija". You cannot use character classes \w, \d, [], or . to solve.