# hash defining your folder patterns
my %patterns = (
    AB => 30,
    BC => 50,
    CD => 42,
);

foreach my $pattern ( keys %patterns ) {

    foreach my $folder ( 1 .. $patterns{ $pattern } ) {

        # construct the folder name using the value of
        # $pattern, the value of $folder_name, and sprintf()

        # use make_path() or whatever to create the folder

        foreach my $subfolder ( 1 .. 100 ) {

            # construct the subfolder name
            # create the subfolder

        }

    }

}