MadelineProto/mtproto.php

383 lines
16 KiB
PHP
Raw Normal View History

2016-06-23 23:51:08 +02:00
<?php
2016-07-14 15:15:50 +02:00
set_include_path(get_include_path().PATH_SEPARATOR.dirname(__FILE__).DIRECTORY_SEPARATOR.'libpy2php');
require_once 'libpy2php.php';
require_once 'os_path.php';
require_once 'crypt.php';
require_once 'prime.php';
require_once 'TL.php';
2016-07-15 13:17:53 +02:00
require_once 'vendor/autoload.php';
$struct = new \danog\PHP\Struct();
2016-07-13 21:39:24 +02:00
/**
* Function to get hex crc32
2016-07-14 15:15:50 +02:00
* :param data: Data to encode.
2016-07-13 21:39:24 +02:00
*/
2016-07-14 15:15:50 +02:00
function newcrc32($data)
{
return hexdec(hash('crc32b', $data));
2016-06-23 23:51:08 +02:00
}
2016-07-13 21:39:24 +02:00
2016-06-23 23:51:08 +02:00
/**
2016-07-13 21:39:24 +02:00
* Function to dump the hex version of a string.
2016-07-14 15:15:50 +02:00
* :param what: What to dump.
2016-06-23 23:51:08 +02:00
*/
2016-07-15 15:01:32 +02:00
function hex_dump(...$what)
2016-07-14 15:15:50 +02:00
{
2016-07-19 11:56:05 +02:00
foreach ($what as $w) {
2016-07-15 15:01:32 +02:00
var_dump(bin2hex($w));
}
2016-07-14 15:15:50 +02:00
}
/**
* len.
*
* Get the length of a string or of an array
*
* @param $input String or array to parse
*
* @return int with the length
**/
function len($input)
{
if (is_array($input)) {
2016-07-19 11:56:05 +02:00
return count($input);
2016-06-28 03:10:15 +02:00
}
2016-07-19 11:56:05 +02:00
return strlen($input);
}
2016-07-13 21:39:24 +02:00
/**
* Function to visualize byte streams. Split into bytes, print to console.
2016-07-14 15:15:50 +02:00
* :param bs: BYTE STRING.
2016-07-13 21:39:24 +02:00
*/
2016-07-14 15:15:50 +02:00
function vis($bs)
{
2016-07-13 21:39:24 +02:00
$bs = str_split($bs);
2016-06-23 23:51:08 +02:00
$symbols_in_one_line = 8;
2016-07-13 21:39:24 +02:00
$n = floor(len($bs) / $symbols_in_one_line);
2016-06-23 23:51:08 +02:00
$i = 0;
foreach (pyjslib_range($n) as $i) {
2016-07-14 15:15:50 +02:00
echo $i * $symbols_in_one_line.' | '.implode(' ',
array_map(function ($el) {
return bin2hex($el);
}, array_slice($bs, $i * $symbols_in_one_line, ($i + 1) * $symbols_in_one_line))
).PHP_EOL;
2016-06-23 23:51:08 +02:00
}
if (len($bs) % $symbols_in_one_line != 0) {
2016-07-14 15:15:50 +02:00
echo($i + 1) * $symbols_in_one_line.' | '.implode(' ',
array_map(function ($el) {
return bin2hex($el);
}, array_slice($bs, ($i + 1) * $symbols_in_one_line))
).PHP_EOL;
2016-06-23 23:51:08 +02:00
}
}
2016-06-26 15:28:39 +02:00
/**
* posmod(numeric,numeric) : numeric
2016-07-19 11:56:05 +02:00
* Works just like the % (modulus) operator, only returns always a postive number.
2016-06-26 15:28:39 +02:00
*/
2016-07-19 11:56:05 +02:00
function posmod($a, $b)
{
$resto = $a % $b;
2016-07-19 11:56:05 +02:00
if ($resto < 0) {
$resto += abs($b);
}
return $resto;
2016-06-26 15:28:39 +02:00
}
2016-06-24 23:47:10 +02:00
2016-07-14 15:15:50 +02:00
function fread_all($handle)
{
2016-06-27 16:52:28 +02:00
$pos = ftell($handle);
fseek($handle, 0);
2016-07-14 15:15:50 +02:00
$content = fread($handle, fstat($handle)['size']);
2016-06-27 16:52:28 +02:00
fseek($handle, $pos);
2016-07-14 15:15:50 +02:00
2016-06-27 16:52:28 +02:00
return $content;
}
2016-07-14 15:15:50 +02:00
function fopen_and_write($filename, $mode, $data)
{
$handle = fopen($filename, $mode);
fwrite($handle, $data);
rewind($handle);
return $handle;
2016-06-28 03:37:04 +02:00
}
2016-06-26 15:28:39 +02:00
/**
* long_to_bytes(n:long, blocksize:int) : string
* Convert a long integer to a byte string.
* If optional blocksize is given and greater than zero, pad the front of the
* byte string with binary zeros so that the length is a multiple of
* blocksize.
*/
2016-07-14 15:15:50 +02:00
function long_to_bytes($n, $blocksize = 0)
{
$s = null;
2016-06-26 15:28:39 +02:00
$n = long($n);
while (($n > 0)) {
2016-07-19 11:56:05 +02:00
$s = $GLOBALS['struct']->pack('I', $n & 4294967295).$s;
2016-06-26 15:28:39 +02:00
$n = $n >> 32;
}
2016-07-14 15:15:50 +02:00
foreach (pyjslib_range(strlen($s)) as $i) {
if (($s[$i] != string2bin('\000')[0])) {
2016-06-26 15:28:39 +02:00
break;
}
}
$s = substr($s, $i);
if ($blocksize > 0 && strlen($s) % $blocksize) {
2016-07-19 11:56:05 +02:00
$s = pack('@'.$blocksize - (strlen($s) % $blocksize)).$s;
2016-06-26 15:28:39 +02:00
}
2016-07-14 15:15:50 +02:00
2016-06-26 15:28:39 +02:00
return $s;
}
/**
* bytes_to_long(string) : long
* Convert a byte string to a long integer.
* This is (essentially) the inverse of long_to_bytes().
*/
function bytes_to_long($s)
{
//return $GLOBALS["struct"]->unpack('>Q', $s)[0];
$acc = 0;
$length = strlen($s);
if ($length % 4) {
$extra = (4 - ($length % 4));
2016-07-19 11:56:05 +02:00
$s = pack('@'.$extra).$s;
$length += $extra;
}
foreach (pyjslib_range(0, $length, 4) as $i) {
2016-07-19 11:56:05 +02:00
$acc = ($acc << 32) + $GLOBALS['struct']->unpack('>I', substr($s, $i, 4))[0];
}
2016-07-19 11:56:05 +02:00
return $acc;
}
2016-07-14 15:15:50 +02:00
function string2bin($string)
{
2016-07-14 12:43:38 +02:00
$res = null;
2016-07-14 15:15:50 +02:00
foreach (explode('\\', $string) as $s) {
if ($s != null && strlen($s) == 3) {
2016-07-14 12:43:38 +02:00
$res .= hex2bin(substr($s, 1));
}
}
2016-07-14 15:15:50 +02:00
2016-07-14 12:43:38 +02:00
return $res;
}
2016-06-23 23:51:08 +02:00
/**
2016-07-14 15:15:50 +02:00
* Manages TCP Transport. encryption and message frames.
2016-06-23 23:51:08 +02:00
*/
2016-07-14 15:15:50 +02:00
class Session
{
public function __construct($ip, $port, $auth_key = null, $server_salt = null)
{
$this->sock = fsockopen('tcp://'.$ip.':'.$port);
if (!(get_resource_type($this->sock) == 'file' || get_resource_type($this->sock) == 'stream')) {
throw new Exception("Couldn't connect to socket.");
}
2016-06-23 23:51:08 +02:00
$this->number = 0;
$this->timedelta = 0;
2016-06-26 14:53:16 +02:00
$this->session_id = random_bytes(8);
2016-06-23 23:51:08 +02:00
$this->auth_key = $auth_key;
2016-07-15 15:01:32 +02:00
$this->auth_key_id = $this->auth_key ? substr(sha1($this->auth_key, true), -8) : null;
2016-06-27 22:52:07 +02:00
stream_set_timeout($this->sock, 5);
2016-06-23 23:51:08 +02:00
$this->MAX_RETRY = 5;
$this->AUTH_MAX_RETRY = 5;
2016-07-14 12:43:38 +02:00
$this->struct = new \danog\PHP\Struct();
2016-07-18 18:43:50 +02:00
$this->PrimeModule = new PrimeModule();
try {
2016-07-14 15:15:50 +02:00
$this->tl = new TL('https://core.telegram.org/schema/mtproto-json');
} catch (Exception $e) {
$this->tl = new TL(__DIR__.'/TL_schema.JSON');
}
2016-06-23 23:51:08 +02:00
}
2016-07-14 15:15:50 +02:00
public function __destruct()
{
2016-06-26 14:53:16 +02:00
fclose($this->sock);
2016-06-23 23:51:08 +02:00
}
2016-07-14 15:15:50 +02:00
2016-06-23 23:51:08 +02:00
/**
* Forming the message frame and sending message to server
2016-07-14 15:15:50 +02:00
* :param message: byte string to send.
2016-06-23 23:51:08 +02:00
*/
2016-07-14 15:15:50 +02:00
public function send_message($message_data)
{
$message_id = $this->struct->pack('<Q', (int) ((time() + $this->timedelta) * pow(2, 30)) * 4);
2016-06-28 03:10:15 +02:00
2016-06-23 23:51:08 +02:00
if (($this->auth_key == null) || ($this->server_salt == null)) {
2016-07-14 15:15:50 +02:00
$message = string2bin('\x00\x00\x00\x00\x00\x00\x00\x00').$message_id.$this->struct->pack('<I', strlen($message_data)).$message_data;
2016-06-23 23:51:08 +02:00
} else {
2016-07-14 12:43:38 +02:00
$encrypted_data =
2016-07-14 15:15:50 +02:00
$this->server_salt.$this->session_id.$message_id.$this->struct->pack('<II', $this->number, strlen($message_data)).$message_data;
2016-07-15 15:01:32 +02:00
$message_key = substr(sha1($encrypted_data, true), -16);
$padding = random_bytes(posmod(-strlen($encrypted_data), 16));
2016-07-14 15:15:50 +02:00
echo strlen($encrypted_data.$padding).PHP_EOL;
2016-06-23 23:51:08 +02:00
list($aes_key, $aes_iv) = $this->aes_calculate($message_key);
2016-07-14 15:15:50 +02:00
$message = $this->auth_key_id.$message_key.crypt::ige_encrypt($encrypted_data.$padding, $aes_key, $aes_iv);
2016-06-23 23:51:08 +02:00
}
2016-07-14 15:15:50 +02:00
$step1 = $this->struct->pack('<II', (strlen($message) + 12), $this->number).$message;
$step2 = $step1.$this->struct->pack('<I', newcrc32($step1));
2016-06-26 14:53:16 +02:00
fwrite($this->sock, $step2);
2016-07-14 12:43:38 +02:00
$this->number += 1;
2016-06-23 23:51:08 +02:00
}
2016-07-14 15:15:50 +02:00
2016-06-23 23:51:08 +02:00
/**
* Reading socket and receiving message from server. Check the CRC32.
*/
2016-07-14 15:15:50 +02:00
public function recv_message()
{
2016-06-26 14:53:16 +02:00
$packet_length_data = fread($this->sock, 4);
if (len($packet_length_data) < 4) {
2016-06-27 18:53:15 +02:00
throw new Exception('Nothing in the socket!');
2016-06-23 23:51:08 +02:00
}
2016-07-15 15:01:32 +02:00
$packet_length = $this->struct->unpack('<I', $packet_length_data)[0];
2016-06-26 14:53:16 +02:00
$packet = fread($this->sock, ($packet_length - 4));
2016-07-15 15:01:32 +02:00
if (!(newcrc32($packet_length_data.substr($packet, 0, -4)) == $this->struct->unpack('<I', substr($packet, -4))[0])) {
2016-06-27 18:53:15 +02:00
throw new Exception('CRC32 was not correct!');
2016-06-23 23:51:08 +02:00
}
2016-07-15 15:01:32 +02:00
$x = $this->struct->unpack('<I', substr($packet, 0, 4));
$auth_key_id = substr($packet, 4, 8);
if ($auth_key_id == string2bin('\x00\x00\x00\x00\x00\x00\x00\x00')) {
2016-07-15 15:01:32 +02:00
list($message_id, $message_length) = $this->struct->unpack('<8sI', substr($packet, 12, 12));
$data = substr($packet, 24, (24 + $message_length) - 24);
2016-07-14 15:15:50 +02:00
} elseif ($auth_key_id == $this->auth_key_id) {
$message_key = substr($packet, 12, 28 - 12);
$encrypted_data = substr($packet, 28, -4 - 28);
2016-07-14 15:15:50 +02:00
list($aes_key, $aes_iv) = $this->aes_calculate($message_key, 'from server');
2016-06-23 23:51:08 +02:00
$decrypted_data = crypt::ige_decrypt($encrypted_data, $aes_key, $aes_iv);
assert((substr($decrypted_data, 0, 8 - 0) == $this->server_salt));
assert((substr($decrypted_data, 8, 16 - 8) == $this->session_id));
$message_id = substr($decrypted_data, 16, 24 - 16);
$seq_no = $this->struct->unpack('<I', substr($decrypted_data, 24, 28 - 24)) [0];
$message_data_length = $this->struct->unpack('<I', substr($decrypted_data, 28, 32 - 28)) [0];
$data = substr($decrypted_data, 32, (32 + $message_data_length) - 32);
2016-06-23 23:51:08 +02:00
} else {
2016-06-27 18:53:15 +02:00
throw new Exception('Got unknown auth_key id');
2016-06-23 23:51:08 +02:00
}
2016-07-14 15:15:50 +02:00
2016-06-23 23:51:08 +02:00
return $data;
}
2016-07-14 15:15:50 +02:00
public function method_call($method, $kwargs)
{
foreach (range(1, $this->MAX_RETRY) as $i) {
2016-06-23 23:51:08 +02:00
try {
2016-06-27 16:52:28 +02:00
//var_dump(py2php_kwargs_function_call('serialize_method', [$method], $kwargs));
$this->send_message($this->tl->serialize_method($method, $kwargs));
2016-06-23 23:51:08 +02:00
$server_answer = $this->recv_message();
2016-07-14 15:15:50 +02:00
} catch (Exception $e) {
echo $e->getMessage().PHP_EOL;
2016-06-23 23:51:08 +02:00
pyjslib_printnl('Retry call method');
continue;
}
2016-07-19 11:56:05 +02:00
2016-07-14 15:15:50 +02:00
return $this->tl->deserialize(fopen_and_write('php://memory', 'rw+b', $server_answer));
2016-06-23 23:51:08 +02:00
}
}
2016-07-14 15:15:50 +02:00
public function create_auth_key()
{
2016-06-26 14:53:16 +02:00
$nonce = random_bytes(16);
2016-06-23 23:51:08 +02:00
pyjslib_printnl('Requesting pq');
2016-07-14 15:15:50 +02:00
$ResPQ = $this->method_call('req_pq', ['nonce' => $nonce]);
2016-06-23 23:51:08 +02:00
$server_nonce = $ResPQ['server_nonce'];
$public_key_fingerprint = $ResPQ['server_public_key_fingerprints'][0];
$pq_bytes = $ResPQ['pq'];
2016-06-26 15:28:39 +02:00
$pq = bytes_to_long($pq_bytes);
2016-07-21 11:54:46 +02:00
$opq = new \phpseclib\Math\BigInteger($pq_bytes, 256);
var_dump($pq, $opq->toString()); die;
var_dump($this->PrimeModule->pollard_brent(15));
2016-07-20 20:12:32 +02:00
var_dump($this->PrimeModule->primefactors(1724114033281923457));
2016-07-19 11:56:05 +02:00
var_dump($this->PrimeModule->primefactors(378221), $this->PrimeModule->primefactors(15));
die;
2016-07-18 18:43:50 +02:00
list($p, $q) = $this->PrimeModule->primefactors($pq);
if ($p > $q) {
2016-06-23 23:51:08 +02:00
list($p, $q) = [$q, $p];
}
assert((($p * $q) == $pq) && ($p < $q));
pyjslib_printnl(sprintf('Factorization %d = %d * %d', [$pq, $p, $q]));
2016-06-26 15:28:39 +02:00
$p_bytes = long_to_bytes($p);
$q_bytes = long_to_bytes($q);
2016-07-14 15:15:50 +02:00
$f = pyjslib_open(__DIR__.'/rsa.pub');
2016-06-23 23:51:08 +02:00
$key = RSA::importKey($f->read());
2016-06-26 14:53:16 +02:00
$new_nonce = random_bytes(32);
2016-07-14 15:15:50 +02:00
$data = py2php_kwargs_function_call('serialize_obj', ['p_q_inner_data'], ['pq' => $pq_bytes, 'p' => $p_bytes, 'q' => $q_bytes, 'nonce' => $nonce, 'server_nonce' => $server_nonce, 'new_nonce' => $new_nonce]);
2016-06-23 23:51:08 +02:00
$sha_digest = sha($data, true);
2016-06-28 03:10:15 +02:00
$random_bytes = random_bytes(((255 - strlen($data)) - strlen($sha_digest)));
2016-06-23 23:51:08 +02:00
$to_encrypt = (($sha_digest + $data) + $random_bytes);
$encrypted_data = $key->encrypt($to_encrypt, 0) [0];
pyjslib_printnl('Starting Diffie Hellman key exchange');
2016-07-14 15:15:50 +02:00
$server_dh_params = $this->method_call('req_DH_params', ['nonce' => $nonce, 'server_nonce' => $server_nonce, 'p' => $p_bytes, 'q' => $q_bytes, 'public_key_fingerprint' => $public_key_fingerprint, 'encrypted_data' => $encrypted_data]);
2016-06-23 23:51:08 +02:00
assert(($nonce == $server_dh_params['nonce']));
assert(($server_nonce == $server_dh_params['server_nonce']));
$encrypted_answer = $server_dh_params['encrypted_answer'];
$tmp_aes_key = (sha1(($new_nonce + $server_nonce), true) + array_slice(sha1(($server_nonce + $new_nonce), true), 0, 12 - 0));
$tmp_aes_iv = ((array_slice(sha1(($server_nonce + $new_nonce), true), 12, 20 - 12) + sha1(($new_nonce + $new_nonce), true)) + array_slice($new_nonce, 0, 4 - 0));
$answer_with_hash = crypt::ige_decrypt($encrypted_answer, $tmp_aes_key, $tmp_aes_iv);
2016-07-15 15:01:32 +02:00
$answer_hash = array_slice($answer_with_hash, 0, 20);
$answer = array_slice($answer_with_hash, 20);
2016-06-27 16:52:28 +02:00
$server_DH_inner_data = deserialize(io::BytesIO($answer));
2016-06-23 23:51:08 +02:00
assert(($nonce == $server_DH_inner_data['nonce']));
assert(($server_nonce == $server_DH_inner_data['server_nonce']));
$dh_prime_str = $server_DH_inner_data['dh_prime'];
$g = $server_DH_inner_data['g'];
$g_a_str = $server_DH_inner_data['g_a'];
$server_time = $server_DH_inner_data['server_time'];
2016-06-27 16:52:28 +02:00
$this->timedelta = ($server_time - time());
2016-06-23 23:51:08 +02:00
pyjslib_printnl(sprintf('Server-client time delta = %.1f s', $this->timedelta));
$dh_prime = new bytes_to_long($dh_prime_str);
$g_a = new bytes_to_long($g_a_str);
2016-07-18 18:43:50 +02:00
assert($this->PrimeModule->isprime($dh_prime));
2016-06-23 23:51:08 +02:00
$retry_id = 0;
2016-06-26 14:53:16 +02:00
$b_str = random_bytes(256);
2016-06-23 23:51:08 +02:00
$b = new bytes_to_long($b_str);
$g_b = pow($g, $b, $dh_prime);
$g_b_str = new long_to_bytes($g_b);
2016-07-14 15:15:50 +02:00
$data = py2php_kwargs_function_call('serialize_obj', ['client_DH_inner_data'], ['nonce' => $nonce, 'server_nonce' => $server_nonce, 'retry_id' => $retry_id, 'g_b' => $g_b_str]);
2016-06-23 23:51:08 +02:00
$data_with_sha = (sha1($data, true) + $data);
$data_with_sha_padded = ($data_with_sha + random_bytes(posmod(-strlen($data_with_sha), 16)));
2016-06-23 23:51:08 +02:00
$encrypted_data = crypt::ige_encrypt($data_with_sha_padded, $tmp_aes_key, $tmp_aes_iv);
foreach (pyjslib_range(1, $this->AUTH_MAX_RETRY) as $i) {
2016-07-14 15:15:50 +02:00
$Set_client_DH_params_answer = $this->method_call('set_client_DH_params', ['nonce' => $nonce, 'server_nonce' => $server_nonce, 'encrypted_data' => $encrypted_data]);
2016-06-23 23:51:08 +02:00
$auth_key = pow($g_a, $b, $dh_prime);
$auth_key_str = new long_to_bytes($auth_key);
$auth_key_sha = sha1($auth_key_str, true);
2016-07-15 15:01:32 +02:00
$auth_key_aux_hash = array_slice($auth_key_sha, 0, 8);
$new_nonce_hash1 = array_slice(sha1($new_nonce.''.$auth_key_aux_hash, true), -16);
$new_nonce_hash2 = array_slice(sha1($new_nonce.''.$auth_key_aux_hash, true), -16);
$new_nonce_hash3 = array_slice(sha1($new_nonce.''.$auth_key_aux_hash, true), -16);
2016-06-23 23:51:08 +02:00
assert(($Set_client_DH_params_answer['nonce'] == $nonce));
assert(($Set_client_DH_params_answer['server_nonce'] == $server_nonce));
if (($Set_client_DH_params_answer->name == 'dh_gen_ok')) {
assert(($Set_client_DH_params_answer['new_nonce_hash1'] == $new_nonce_hash1));
pyjslib_printnl('Diffie Hellman key exchange processed successfully');
$this->server_salt = new strxor(array_slice($new_nonce, 0, 8 - 0), array_slice($server_nonce, 0, 8 - 0));
$this->auth_key = $auth_key_str;
2016-07-15 15:01:32 +02:00
$this->auth_key_id = array_slice($auth_key_sha, -8);
2016-06-23 23:51:08 +02:00
pyjslib_printnl('Auth key generated');
2016-07-14 15:15:50 +02:00
2016-06-23 23:51:08 +02:00
return 'Auth Ok';
2016-07-14 15:15:50 +02:00
} elseif (($Set_client_DH_params_answer->name == 'dh_gen_retry')) {
2016-06-23 23:51:08 +02:00
assert(($Set_client_DH_params_answer['new_nonce_hash2'] == $new_nonce_hash2));
pyjslib_printnl('Retry Auth');
2016-07-14 15:15:50 +02:00
} elseif (($Set_client_DH_params_answer->name == 'dh_gen_fail')) {
2016-06-23 23:51:08 +02:00
assert(($Set_client_DH_params_answer['new_nonce_hash3'] == $new_nonce_hash3));
pyjslib_printnl('Auth Failed');
2016-06-27 18:53:15 +02:00
throw new Exception('Auth Failed');
2016-06-23 23:51:08 +02:00
} else {
2016-06-27 18:53:15 +02:00
throw new Exception('Response Error');
2016-06-23 23:51:08 +02:00
}
}
}
2016-07-14 15:15:50 +02:00
public function aes_calculate($msg_key, $direction = 'to server')
{
2016-06-23 23:51:08 +02:00
$x = ($direction == 'to server') ? 0 : 8;
$sha1_a = sha1(($msg_key + array_slice($this->auth_key, $x, ($x + 32) - $x)), true);
$sha1_b = sha1(((array_slice($this->auth_key, ($x + 32), ($x + 48) - ($x + 32)) + $msg_key) + array_slice($this->auth_key, (48 + $x), (64 + $x) - (48 + $x))), true);
$sha1_c = sha1((array_slice($this->auth_key, ($x + 64), ($x + 96) - ($x + 64)) + $msg_key))->digest();
$sha1_d = sha1(($msg_key + array_slice($this->auth_key, ($x + 96), ($x + 128) - ($x + 96))))->digest();
$aes_key = ((array_slice($sha1_a, 0, 8 - 0) + array_slice($sha1_b, 8, 20 - 8)) + array_slice($sha1_c, 4, 16 - 4));
$aes_iv = (((array_slice($sha1_a, 8, 20 - 8) + array_slice($sha1_b, 0, 8 - 0)) + array_slice($sha1_c, 16, 20 - 16)) + array_slice($sha1_d, 0, 8 - 0));
2016-07-14 15:15:50 +02:00
2016-06-23 23:51:08 +02:00
return [$aes_key, $aes_iv];
}
}