How should i record my cost basis in my portfolio tracker if i trade one stock for other

Maybe a dumb question, but please help me out.

I use Yahoo Finance to keep track of all the stocks I have been buying for some time. Every time I buy a stock, I enter the number of shares I acquired and the price I paid for them. This has been pretty straightforward since I simply enter the amount of USD paid for each stock.

A couple of years later, I check my portfolio and decide to sell some stocks, some with a profit and some with a loss. With the proceeds, I plan to reallocate them to other stocks. This is where my doubts arise: What value should I enter as cost basis for the new stocks I am buying? If I enter the amount of USD I received from the sale, whether it was a profit or a loss, my total portfolio return won't be accurate in my opinion since i am leaving out either the profit or the loss.

Should I enter the amount of USD I originally paid when I bought the stocks I sold?

The goal is to have my total portfolio return accurately reflect the value I have invested overall.

Thanks