Creating new li elemnt on last li change

Question

I have this ul element

   <ul style="  list-style-type: none;" id="cams_ul">
                                    <?php for($i= 1 ; $i <= $total_items ; $i++ ) : ?>
                                       <li id="rmv_cam<?= $i ?>"><button type="button" id="rmv_cam<?= $i ?>"  class="btn btn-error btn-sm remove_cam"><i class="fa fa-minus-circle"></i> </button>  פריט מחסן  :&nbsp<input type="text" name="cam[]" id="get_prod<?= $i ?>" data-i = "<?= $i ?>" class="form-control w-25 mt-3 prod"  ><div class="prd_warp"><span class="prd_info" id="pdr_info<?= $i ?>"></span></div></li>
                                    <?php endfor; ?>
                                </ul>

and I have this script that creates a new li on change

 $( "li" ).last().on('change',function () {
    num++;
    $('#cams_ul').append(' <li id="rmv_cam'+num+'" ><button type="button"  id="rmv_cam'+num+'"  class="btn btn-error btn-sm remove_cam"><i class="fa fa-minus-circle"></i> </button>  פריט מחסן  :&nbsp<input type="text" name="cam[]" id="get_lens'+num+'" data-i = "'+num+'" class="form-control w-25 mt-3 prod"  ><div class="prd_warp"><span class="prd_info" id="pdr_info'+num+'"></span></div></li>');
} );

my problem is that when the new li is created the last function is not responding to the last append elemet that created