02. Numbers 1 to 20

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<?php
    echo "<ul>";
echo "<li><span style='color: blue'>1</span> </li>";
echo "<li><span style='color: green'>2</span> </li>";
echo "<li><span style='color: blue'>3</span> </li>";
echo "<li><span style='color: green'>4</span> </li>";
echo "<li><span style='color: blue'>5</span> </li>";
echo "<li><span style='color: green'>6</span> </li>";
echo "<li><span style='color: blue'>7</span> </li>";
echo "<li><span style='color: green'>8</span> </li>";
echo "<li><span style='color: blue'>9</span> </li>";
echo "<li><span style='color: green'>10</span> </li>";
echo "<li><span style='color: blue'>11</span> </li>";
echo "<li><span style='color: green'>12</span> </li>";
echo "<li><span style='color: blue'>13</span> </li>";
echo "<li><span style='color: green'>14</span> </li>";
echo "<li><span style='color: blue'>15</span> </li>";
echo "<li><span style='color: green'>16</span> </li>";
echo "<li><span style='color: blue'>17</span> </li>";
echo "<li><span style='color: green'>18</span> </li>";
echo "<li><span style='color: blue'>19</span> </li>";
echo "<li><span style='color: green'>20</span> </li>";
    echo "</ul>";
?>
</body>
</html>