Help me in solving HTML18 problem

My issue

Learning course: Learn HTML / CSS
Problem Link: CodeChef: Practical coding for everyone

<u>
    Greece officially the Hellenic Republic
</u>
<ul>
    <li>It is a country in south East Europe</li>
    <li>Greece has the longest coastline on the Mediterranean Basin</li>
    <li>It has thousands of islands.</li>
</ul>