Form formula to allow different calculation for rows 1 and 2 than the rest of the rows in the same c

Summary

Is it possible to enter a form formula column that will perform a certain calculation for rows 1 and 2, but a different calculation for the rest of the rows?

Content

I am working on a planning and budgeting cloud form. In that form, I want to have a formula column that subtracts column A from C for rows 1 and 2 only. I want the rest of the column to subtract C from A for all the other rows. Is that even possible? I have tried a few different formulas but it gives me a syntax or a circular reference warning every time.