Assuming you mean that element "nani" doesn't get updated it is because you are attempting to set the value using
and you do not have any elements with that Id.
You do have an element with that name
<input type="number" name="nani" required </p>
Try changing that to
<input type="number" id="nani" required </p>
Edit: Given that you have more named elements than those with Ids it might be better for you to switch to using Document.getElementsByName()