Insertion of elements before or after in JavaScript

Задание 1

Given an ul:

html<ul id="elem">
  <li>text</li>
  <li>text</li>
  <li>text</li>
  <li>text</li>
  <li>text</li>
</ul>

Insert an element with the text 'start' at the beginning, and an element with the text 'finish' at the end of it.