<div class="block">
  <div class="block-info">
    <ul class="block-list">
      <li class="block-item">
        <a href="#" class="item-link">1</a>
      </li>
    </ul>
  </div>
</div>

.block {
  //...
  &-info {
    //...
  }
  &-list {
    //...
  }
  &-item {
    //...
    &-link {
      
    }
  }
}