#!/usr/bin/perl

use strict;
use warnings;

use Math::BigInt;

$_ = "DEADBEEFBABEFACE1234567890";

my $num = Math::BigInt -> new (0);

# Convert the number to a Math::Int decimal number.
while (length) {
    my $chunk = substr $_, 0, 4, "";
    $num *= 2 ** (4 * length $chunk);
    $num  += hex $chunk;
}

# Multiply by 2, add 1.
$num *= 2;
$num += 1;

# Convert the Math::BigInt number to hex.
my @a;
while ($num) {
    push @a => sprintf "%X" => $num % 16;
    $num /= 16;
}
my $new = join "" => @a;

print $new, "\n";

##</code><code>##

#!/usr/bin/perl

use strict;
use warnings;

use Inline 'BC';

print x("DEADBEEFBABEFACE1234567890");

__DATA__
__BC__
ibase = 16
obase = 10
define x (a) {
    return (a * 2 + 1)
}