I have to use only 3 cells. Let's say A1 for initial inventory amount, C1 for total balance of inventory, and B1 which is the cell where i have to input daily the quantity used which is deducted from cell A1.

I need that C1 show everytime the new result when i input the new quantity used daily.

I can not use more rows nor more cells because the are filled with other data as well as I receive daily new inventory with different items that are used daily.