#!/usr/bin/perl -w
use strict;
use Carp;

my @d = <>;

sub l_ok ($) {
    my ($i) = @_;
    return unless $i < @d;
    $_ = $d[$i];
    1;
}

sub l ($) { confess unless l_ok $_[0]; };

our ($ifilehead, $ihunkhead, $ichunk);
our ($before, $after);

for ($ifilehead = 0; l_ok $ifilehead; $ifilehead++) {
    m{^diff} or next;
    while (l_ok $ifilehead and m{^index|^---|^\Q+++\E}) { }
    $ihunkhead = $ifilehead;
    while (l_ok $ihunkhead) {
	m{^\@\@} or confess;
	$ichunk = $ihunkhead + 1;
	for (;;) {
	    l_ok $ichunk or last;
	    
	while (l_ok $ichunk and 
    }
	
    confess unless m{^\@\@};
	   

while (<>){
    if (m/^diff.*/) {
	my $headline = 
}