# What am I doing wrong here? (i.e. inserting incremental letter)

**URL:** https://community.mp3tag.de/t/what-am-i-doing-wrong-here-i-e-inserting-incremental-letter/65127
**Category:** Support
**Created:** [June 24, 2024, 4:24pm UTC](https://community.mp3tag.de/t/what-am-i-doing-wrong-here-i-e-inserting-incremental-letter/65127 "2024-06-24T16:24:58Z")
**Posts on this page:** 1
**Showing post:** 2

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### Author: ![ohrenkino](https://community.mp3tag.de/user_avatar/community.mp3tag.de/ohrenkino/32/4843_2.png) [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [June 24, 2024, 5:04pm UTC](https://community.mp3tag.de/t/what-am-i-doing-wrong-here-i-e-inserting-incremental-letter/65127/2 "2024-06-24T17:04:12Z")

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If %1 represents the whole filename, then

> [@cmach1](#):
>
> $num(%1,1)

will always be `0` as an "A" is no number and therefore the numeric value = 0.  
see also your post from a couple of days ago:

> [@How to get an incremental letter](https://community.mp3tag.de/t/how-to-get-an-incremental-letter/64970/5):
>
> You would have to supply the original filename, the pattern you used for the original filename and the pattern for the target filename. If A1 is the %1 part, then $num(%1,1) will always return 0 as value.

To get an incremented letter at the end of the filename of the selected files, do not use Convert\>Filename-Filename but Convert\>Tag-Filename  
Format string: `%_filename% - $char($add(64,%_counter%))`

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