PHP Artisan migrate: Class Schema not found

I am studying Laravel 5.4 and I have the following problem:

When performing a migration, in the console of Windows I execute the command:

php artisan migrate

When executing this command, it shows me the following error:

  

[Symfony \ Component \ Debug \ Exception \ FatalErrorException] Class   'Market \ Providers \ Schema' not found

How can I solve Class Schema not found ? annex the migration code:

-To create the product table:

<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class CreateProductTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('products', function (Blueprint $table){
            $table->increments('id');
            $table->string('name',100);
            $table->decimal('price',5,2);
            $table->integer('marks_id')->unsigned();
            $table->foreign('marks_id')->references('id')->on('marks');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::drop('products');
    }
}

-To create the Brand Table

<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class CreateMarkTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('marks', function (Blueprint $table){
            $table->increments('id');
            $table->string('name',50);
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::drop('marks');
    }
}

-Code of AppServiceProvider.php

<?php

namespace Market\Providers;

use Illuminate\Support\ServiceProvider;

class AppServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap any application services.
     *
     * @return void
     */
    public function boot()
    {
        Schema::defaultStringLength(191);
    }

    /**
     * Register any application services.
     *
     * @return void
     */
    public function register()
    {
        //
    }
}