count in order according to class
HTML
<ol>
<li class="count">one</li>
<li class="count">two</li>
<li class="count">three</li>
<li class="count">four</li>
<li>blabla</li>
<li class="count">five</li>
<li class="count">six</li>
<li>blabla</li>
<li class="count">seven</li>
</ol>
CSS
li {
list-style-type: decimal;
}
li:not(.count) {
list-style-type: none;
}