You are given a string s typed by a user. Changing a key is defined as typing a character that is different from the immediately preceding character, ignoring letter casing.

Return the number of times the key was changed while typing s.

Note: Modifiers such as Shift or Caps Lock do not count toward a key change. For instance, typing 'a' followed by 'A' uses the same key.

Constraints:

• $1 \leq$ s.length $\leq 100$

• s consists of only upper case and lower case English letters.

Now, let’s take a moment to make sure you’ve correctly understood the problem. The quiz below helps you check if you’re solving the correct problem:

We have a game for you to play. Rearrange the logical building blocks to develop a clearer understanding of how to solve this problem.

Implement your solution in the following coding playground.