Class 'Illuminate\Support\Facades\Input' not found

看了API文档，也是Illuminate\Support\Facades\Input啊，奇怪了

controller

<?php

namespace App\Http\Controllers;

use DB;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Input;

class SearchController extends Controller
{
    public function result()
    {
        $input = Input::except('_token');
        $keyword = $input['keyword'];

        dump($input, $keyword);
    }
}

报错

Class 'Illuminate\Support\Facades\Input' not found

但是我引用了use Illuminate\Support\Facades\Input;，所以引用地址错了？正确的是什么？