$data = file("ttttt.txt");
$users = array();
foreach ($data as $row) {
$tmp = explode("<>", $row);
$users[$tmp[0]] = $tmp[1];
}
$tmp[0] = $_POST['username'];
$tmp[1] = $_POST['password'];
if ($tmp[0] != '' && $tmp[1] != '') {
if ($tmp[1] == $users[$tmp[0]]) $_SESSION['username'] = $tmp[0];
else unset($_SESSION['username']);
}

hoge<>geho
aaaa<>bbbb
1111<>2222

なぜか1111<>2222しかログインできない・・・。
何がいかないんでしょうか?