Need help using IF statements to ignore the first row, then follow through with the math

I'm trying to set up a ledger essentially to keep track of purchases and sales.

What I have in mind is in A1 to be the total cash, set up to add the value of the action based on if the action is declared a buy or sell.

A2 would say "Action" with the rest of the column from A3 onto forever, saying "buy" or "sell"

Column B would have the value of the action


How can I set up A1 to show a dollar amount that adds what's in B for "sell" and subtracts B for "buy".


I currently have A1=IF(A:A="buy",-B:B,IF(A:A="sell", +B:B)). However, this causes an error.

Any help would be greatly appreciated, ahead of time.