i write a jquery code but it doesnt work as i expected

Question

I want when I click on add to add an elements in the .items and then when I click "remove" remove it but it doesn't work

$('.add').on('click', function () {
      $('.items').append('<span class="rmv">remove</span>');
});
$('.rmv').on('click', function() {
       $(this).remove(); 
});
    

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="items"></div>
<div>
   <span class="add">add</span>
</div>