#!/usr/bin/perl -w
use strict;
use warnings;
use List::Util qw (max);

my %hash = (
1   => defined,
4   => defined,
8   => defined,
10  => defined,
);

print "max: " . max(keys %hash) . "\n";
my %kopie = %hash;
delete $kopie{max(keys %hash)};
print "zweitmax: " . max(keys %kopie) . "\n";