RSS2 feed

I have <pre>
<?php echo ‘<?xml version=”1.0″?’.’>’; ?>
<?php
$blog = 1;
$doing_rss = 1;
header(‘Content-type: text/xml’, true);
require(‘wp-blog-header.php’);
/* This doesn’t take into account edits
// Get the time of the most recent article
$maxdate = $wpdb->get_var(“SELECT max(post_date) FROM $tableposts”);
$unixtime = strtotime($maxdate);
// format timestamp for Last-Modified header
$clast = gmdate(“D, d M Y H:i:s \G\M\T”, $unixtime);
$cetag = (isset($clast)) ? md5($clast) : ”;
// send it in a Last-Modified header
header(“Last-Modified: ” . $clast, true);
header(“Etag: ” . $cetag, true);
*/
if (!isset($rss_language)) { $rss_language = ‘en’; }
if (!isset($rss_encoded_html)) { $rss_encoded_html = 0; }
if (!isset($rss_excerpt_length) || ($rss_encoded_html == 1)) { $rss_excerpt_length = 0; }
?>
<rss version=”2.0″
xmlns:content=”https://purl.org/rss/1.0/modules/content/”&gt;
<channel>
<?php $items_count = 0; if ($posts) { foreach ($posts as $post) { start_wp(); ?>
<item>
<content:encoded><?php the_content(”, 0, ”) ?></content:encoded>
</item>
<?php $items_count++; if (($items_count == $posts_per_rss) && empty($m)) { break; } } } ?>
</channel>
</rss>
</pre>
but I want it only to show the latest piece of news.