How to exclude some letters from numbered list with letters in MS WORD?

Question

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I make a list of the form in ms word:
Appendix A
Appendix B
...
How to exclude some letters from the list, for example Z , which cannot be used, since it looks like the number 3 ?
Numbering by hand is not kosher.
upd:
So far the issue has been resolved by the trace. way: I selected the Appendix H item and set a new initial value, while the previous items did not seem to go anywhere and the content is normally formed.