How to enter ESPP stock sale that has split twice after the original purchase and 1099 has 2 separate entries for the original shares and split shares?

In my 1099-B, my broker has listed 2 separate sale transactions for ESPP stocks; one for the original purchase of  50 shares (purchased at $10/ share) and the second for the split 50 shares. This stock was split 2:1 few years back. Should I enter these 2 sales separately for each of these 50 shares, or should I enter one combined 100 shares? How would I calculate the cost basis since I only paid $500 for the original 50 shares?