AltoRouter does not enter in map method

Question

Hello I download AltoRouter manuely and I try it the connection is good in the AltoRouter.php class but when I run the code in map fonction doesn't be executed. Here it's my code.

<?php  require('../foldername/foldername/AltoRouter.php');
 //require('header01.php');
 //require('header02.php');

 $router = new AltoRouter();
  $router->map('GET','/',function(){
   echo 'papa';// this code doesn't be executed when I run the app
 });
 //require('footer.php');
?>

If someone can help me.