sub dump_hash_maker {
     my ($ltrStart, $size) = @_;

     my $stop = chr (ord($ltrStart)+$size);
     my @letters;
     push @letters, $_ for ($ltrStart..$stop);
     my %hash = map {(shift @letters)=>$_} (1..$size) ; 
     return %hash;     

}

my %hash1 = dump_hash_maker('A',4);
my %hash2 = dump_hash_maker('D',7);
my %hash3 = dump_hash_maker('J',13);

my @allkeys = ();
my (%intermediate);

push @allkeys,(keys %hash1);
push @allkeys,(keys %hash2);
push @allkeys,(keys %hash3);
for(@allkeys)
{
    $intermediate{$_}++;
}
for(keys %intermediate) {print $_ if $intermediate{$_} > 1};
# prints JD