use Fcntl qw(SEEK_SET);

use strict;

# Calculate Relationships.
# - Rely on increment, as it's the easier of the two to calculate.
my %decrement;
my %increment; # Synonymous with existance.

my $start_of_DATA = tell DATA;

while (<DATA>) {
	chomp;
	my $item = $_;
	
	# Note concerning parsing
	# - This regex requires that a prefix exist.
	if ($item =~ m{ (\w+) ( (?<!\d)\d+ | (?<![A-Z])[A-Z]+ ) \z}x) {
		my ($prefix, $suffix) = ($1, $2);
		
		# Note: this is the primary spot where there might be changes in rules.
		# - What happens when the character ends in 'Z'?  Currently
		#   That would translate to 'AA'.
		# - What happens when number is 999?  Currently that would translate
		#   to '1000'.
		# Fix the rules here, and everything else will translate.
		(my $suffix_next = $suffix)++;
		
		my $item_next = $prefix . $suffix_next;
		$increment{$item} = $item_next;
		$decrement{$item_next} = $item;
		
	} else {
		die "Invalid data: $_";
	}
}

# Reparse DATA
seek(DATA, $start_of_DATA, SEEK_SET);

while (<DATA>) {
	chomp;

	print;
	if ($increment{ $decrement{ $_ } }) {
		print ";$decrement{$_}";
	} elsif ($increment{ $increment{ $_ } }) {
		print ";$increment{$_}";
	}
	print "\n";
}

__DATA__
AAA30
BBC5
SHT12H
DAL33B
BBC49
AAA31
BBC8
BBC3
DAL33A
BBC6
SHT12G
BBC50