mysql_num_rows in laravel?

im trying to use mysql_num_rows in laravel but laravel says it not the same way like in 'raw php'

example:

$users = DB::table('users')
         ->where('username', '=', $username)
         ->where('password', '=', $password)
         ->get();

what i want to do:

$count = mysql_num_rows($users);

   if($count > 0 ){

      $user->login = $request->login;
      $user->email = $request->email;
      $user->password = $request->password;

      Auth::login($user);
      return redirect("/");
      }else{
         return "datos incorrectos";
      }

what laravel says:

Call to undefined function App\Http\Controllers\Auth\mysql_num_rows()

PD: its not philosophy of code just make commets about that question, i dont want answers like "u gonna crypt that thing?", "why not use [insert my faborite ORM]" is just a simple question THANKS

Instead of using mysql_* functions, you should use count() instead. It can be chained to Eloquent, query builder, or collections.

$users_count = DB::table('users')
     ->where('username', '=', $username)
     ->where('password', '=', $password)
     ->count();