Iam not a great guy in regular expression.

I have tried a little with regular expressions.

use strict;
use warnings;
undef $/;
my $str;
($str=<DATA>)=~s{(((\n|^)K (.*?)(?=\n|$))+)}{"$3<p>".${($_=$1)=~s!(\n|
+^)K !,%!g,\$_}."</p>"}eg;
$str=~s/(<p>),/$1/g;
print $str;
[download]

Please forgive any thing i have done silly in the above code.