creating a shift roster, need to add hours

I'm creating a roster where there are 6 kinds of Shift. The D8 (8hr day), D10 (10hr day), LD (10hr late start), E (10hr evening) PH (public holiday 8 hr) & O (off)

I need the final cell in the row to show a running total as I fill the roster, what formula should I use?

Thanks in advance

Kaz

I have no idea how to upload a workbook.... here's a screen dump of the roster. I want to put the total in column AL. I need to ignore or give a 0 value for anything that isn't a shift (such as RL).
roster.jpg

Of course..... 2.5 years away and my brain is fried. Thanks so much for such a simple, neat solution.