You are given a string word. A letter is considered a special character if it appears in word in both its lowercase and uppercase forms.

Return the total number of special characters present in word.

Constraints:

• $1 \leq$ word.length $\leq 50$

• word consists of only lowercase and uppercase English letters.

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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.