How to add selected count feature in Multiselect dropdown with Search and Select box with Search

I want to add this code in my project [1]: https://codepen.io/gazishowrav/pen/yQwgKj But I want to enable the count of selected check boxes feature instead of displaying the labels of selected check boxes. I would appreciate any help.

<style>
  body {
    padding: 50px;
  }
  h1 {
    font-size: 25px;
    border-bottom: 1px solid #aaa;
    padding: 10px 0;
    margin-bottom: 20px;
  }
  .select-box {
    width: 600px;
    margin: 100px auto;
  }
  .bs-searchbox .form-control {
  background-image: url("data:image/png;base64,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");
  background-position: right 10px center;
  background-repeat: no-repeat;
  border-radius: 50px;
  height: 28px;
  padding: 0 10px;
  border: 1px solid #ccc;
  font-size: 12px;
}
</style>
<div class="select-box">
  <select class="selectpicker"  multiple="" data-live-search="true" data-live-search-placeholder="Search" tabindex="-98">
            <optgroup label="Driver Groups">
              <option>BEC</option>
              <option>VMA</option>

            </optgroup>
            <optgroup label="Drivers">
              <option>Stan</option>
              <option>Fanny</option>
              <option>Rudy</option>
              <option>Ahmed</option>
            </optgroup>
           
          </select>
</div>