how to add an arrow in the parent menu?

[taghaboy]

hello,
i hop you understand my question and my English.

i have a menu with 4 links, and every link have sub-menu, how can i add automatically an arrow text or image to the link menu who have sub-menu.
exemple:

her the arrow must to like this link 1 »

<ul>
   <li>
       <a href="#">link 1</a>
                  <ul>
                         <li><a href="#">link 1-1</a></li>
                         <li><a href="#">link 1-2</a></li>
                         <li><a href="#">link 1-3</a></li>
                         <li><a href="#">link 1-4</a></li>
                  </ul>
   </li>
</ul>

thanks