How to create XPath for the tags not having id or name

alt text http://img231.imageshack.us/img231/9558/testxb.png

Please look into the tag sequen开发者_StackOverflowce(click on the link) and want to know xpath for this. None of the tag having ID's or names.

I need to use xpath in the following command.

selenium.click("XPath goes here");

Regards Sai

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//button[@class='hdm-button'][2]