Solution 1:

It is Input and not input. This commit removed Input facade definition from config/app.php hence you have to manually add that in to aliases array as below,

'Input' => Illuminate\Support\Facades\Input::class,

Or You can import Input facade directly as required,

use Illuminate\Support\Facades\Input;

Solution 2:

For laravel < 5.2:

Open config/app.php and add the Input class to aliases:

'aliases' => [
// ...
  'Input' => Illuminate\Support\Facades\Input::class,
// ...
],

For laravel >= 5.2

Change Input:: to Request::