Formula to calculate remaining vacation days from total

My data looks like this:

1 2 3 4 5 6 7 8 9 10 Allowed V-days Remaining V-days
Bears, Don X X X X X 10

What formula can I use under remaining v-days column that will calculate how many days are left?
The answer here is 5 of course, but I want this to change as I add another X to the column as the employee uses their vacation days.

I appreciate any help you can give me.

Thanks.

Tricia

Hi,
Works exactly right!!
Thank you! Thank you!!

Tricia