Excluding files and directories to backup, right path - Backup and Migrate

Hi,

I'm not getting to exclude right directories on Backup and Migrate.
For example, if I specify "modules" (reffering to "public_html/modules") it seems that it also excludes all "modules" directories, even "sites/all/modules".

So, what is the right way, right path to specify on "Exclude the following files or directories" field under Backup and Migrate settings?

Many thanks!