# Replacing leading number in Filename with incremental letters over 26
**URL:** https://community.mp3tag.de/t/replacing-leading-number-in-filename-with-incremental-letters-over-26/65551
**Category:** Support
**Created:** [August 10, 2024, 9:57pm UTC](https://community.mp3tag.de/t/replacing-leading-number-in-filename-with-incremental-letters-over-26/65551 "2024-08-10T21:57:26Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@walb77](https://community.mp3tag.de/u/walb77)
#### Post date: [August 10, 2024, 9:57pm UTC](https://community.mp3tag.de/t/replacing-leading-number-in-filename-with-incremental-letters-over-26/65551/1 "2024-08-10T21:57:26Z")
Hello,
I am trying to get my Apple Watch to keep my audiobook chapters in order using the iCatcher app. iCatcher on my watch uses A-Z (lexicographical) for sorting instead of numbers. Using Mp3tag to sort, I've had luck using "Convert \> Filename - Filename" and entering
Old filename:
%1 - %2 - %3
New filename:
$char($add($num(%1,1),64)) - %2 - %3
This works just fine for audiobooks with 26 or less chapters. This gives me chapter or file names with uppercase letters A-Z. But any audiobook with \> 26 chapters gives me ASCII characters instead of incremental letters (lowercase a-z) which is what I am trying to get.
In other words, I want to be able to sort files A-Z for the first 26 files then a-z for the reminding files. Any ideas? Thanks.
---
### Author:  [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [August 11, 2024, 6:17am UTC](https://community.mp3tag.de/t/replacing-leading-number-in-filename-with-incremental-letters-over-26/65551/2 "2024-08-11T06:17:45Z")
As numbers are also ansi characters, I wonder whether the watch really ignores these when sorting a filename - does it really throw those parts away?
After you reached the magic first 26 characters plus the next bunch you are restricted to 52 files maximum - which is also probably not enough for a fair number of audiobooks.
The easiest way would be:
filter for files with a track number greater 26 and apply the function with a different offset.
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### Author:  [@walb77](https://community.mp3tag.de/u/walb77)
#### Post date: [August 11, 2024, 4:50pm UTC](https://community.mp3tag.de/t/replacing-leading-number-in-filename-with-incremental-letters-over-26/65551/3 "2024-08-11T16:50:35Z")
Thanks for the help ohrenkino. I am trying your solution. Also, I had a typo in my question. I used "ansi characters" when I meant "ASCII characters." Just for clarification. Thanks again.
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### Author:  [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [August 11, 2024, 5:07pm UTC](https://community.mp3tag.de/t/replacing-leading-number-in-filename-with-incremental-letters-over-26/65551/4 "2024-08-11T17:07:13Z")
What happens with filenames like
A001
A002
A003
do these get sorted correctly?
---
### Author:  [@walb77](https://community.mp3tag.de/u/walb77)
#### Post date: [August 12, 2024, 11:34pm UTC](https://community.mp3tag.de/t/replacing-leading-number-in-filename-with-incremental-letters-over-26/65551/5 "2024-08-12T23:34:23Z")
Oh yes, that works. They sort correctly. Thanks for your solution ohrenkino. You have been very helpful. BTW, your Akai GX77 brings back fond memories of my X-165D I bought in the early '70s and still have downstairs.
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### Author:  [@system](https://community.mp3tag.de/u/system)
#### Post date: [September 11, 2024, 11:34pm UTC](https://community.mp3tag.de/t/replacing-leading-number-in-filename-with-incremental-letters-over-26/65551/6 "2024-09-11T23:34:58Z")
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