I want to write a JQuery code that will give me the id of the li (which contains text "Yes") inside form with `id=f1`

In other words the jquery should give me output `l5`

```
<html>

<body>
    <form  id='f1'>         
    <ul>
        <li id='l1'></li>
        <li id='l2'></li>
        <li id='l3'>
            <ul>
                <li id='l4'></li>
                <li id='l5'>Yes</li>            
            </ul>
        </li>
    </ul>

</form>

<form  id='f2'>         
        <ul>
            <li id='x1'></li>
            <li id='x2'></li>
            <li id='x3'>
                <ul>
                    <li id='x4'></li>
                    <li id='x5'>Yes</li>            
                </ul>
            </li>
        </ul>

</form>
</body>
</html>

```