sub alfNum {
    my ($aAlf, $aNum) = $a =~ /([a-z]+)(\d+)/i;
    my ($bAlf, $bNum) = $b =~ /([a-z]+)(\d+)/i;
    
    return $aAlf cmp $bAlf if $aAlf ne $bAlf;
    return $aNum <=> $bNum;
}