#! perl
use strict;
use warnings;
use List::Util 'max';

my %h =
(
   '11c'  => 'C',
    b     => 'B',
    e22   => 'E',
    aaaaa => 'AAAA',
);

if (%h)
{
    my $last = max map { \$_ } values %h;
    printf "The last element added to the hash was %s\n", $$last;
}
else
{
    print "No elements have been added to the hash\n";
}