use strict;

my %ShortToLong =("A"=>"Ambiente","Bed"=>"Bediener","Bl"=>"Blumen","K"=>"Kellner","Bel"=>"Beleuchtung");
my %LongToShort = reverse %ShortToLong;

sub checkit
{
   my ($word) = @_;   
   return $ShortToLong{$word} || $LongToShort{$word} || "";
}

print checkit("A"),"\n";
print checkit("Blumen"),"\n";
print checkit("esskar"),"\n";