User input number minus a set of cells?

Hello!
I have been searching from answers, but to no avail.....
What I am trying to do is:

Have a blank cell for "USERS" to input a number. Then, I have a set of cells where users enter other numbers. What I would like to do is have the first cell with the "USER" inputed number, decrease by the amounts entered into the other cells. I will also need this "USER" inpute cell to count into the negatives. Any help on this is MUCH APPRECIATED!
Thank You!

If you do not want to use a macro, you need another cell

Does this work for you?:

Subtract.xlsx