[jQuery] Text manipulation on a menu

[dogslife]

I'm using a vertical menu and trying to add a text arrow ">" to the
menu item if it's on level 1 or 2, but not level 3. The following code
works, but it just keeps appending after each hover event. What's the
best way to do this kind of manipulation?

Thanks.

jQuery
-------------------
$("ul.nav li a").hover(function() {
    $(this).append(" 〉");
});

HTML
--------------------
<ul class="nav">
    <li><a href="#">Level 1</a>
        <ul>
            <li>
                <a href="#">Level 2</a>
                    <ul>
                        <li><a href="#">Level 3</a></li>
                    </ul>
            </li>
        </ul>
    </li>
</ul>