Automated backups: Maximum number of backups kept

Hello,

we are running Moodle 3.7.

In Automated backup setup we have dropdown menu (Maximum number of backups kept) with these standard options:
All,1,2,5,10,20,30,40,50...

We chosen to keep 5 backups from this dropdown menu.

However I would like to ask if it's possible somehow to set to keep 4 backups?
Maybe we can set it in config.php file or database?

Thanks,
Marius.