#!/usr/bin/env perl

use 5.010;
use strict;
use warnings;

use Getopt::Long;

my $address;

GetOptions('a|address=s' => \$address);

if ($address) {
    my $len;
    my @bytes = split('', $address);

    if (($len = length $address) == 10 &&
        $bytes[0] eq '0' && lc $bytes[1] eq 'x') {
        $address = substr $address, 2, $len;
    }

    say '\x' . join ('\x', reverse ($address =~ m/../g));
}