jquery - Div内の非表示の入力要素の数を数える方法

Question

here is the code :

   <div class="upload"><br>
  <br>
  <br>
  <input type="hidden" value="" id="SWFUpload_0_3" name="jpg_uploaded_files[]">
  <br>
  <input type="hidden" value="" id="SWFUpload_0_4" name="jpg_uploaded_files[]">
  <br>
  <input type="hidden" value="" id="SWFUpload_0_5" name="jpg_uploaded_files[]">
  <br>
  <input type="hidden" value="" id="SWFUpload_0_6" name="jpg_uploaded_files[]">
  <br>
  <input type="hidden" value="" id="SWFUpload_0_7" name="jpg_uploaded_files[]">
  <br>
  <input type="hidden" value="" id="SWFUpload_0_8" name="jpg_uploaded_files[]">
  <br>
</div>