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;