Double Discount

Chef is craving a midnight snack, and so decided to order some food on the ChefEats app. There are $N$ food items available on the ChefEats app. The $i$-th item has a cost of $A_i$ rupees and a tastiness of $B_i$. It is guaranteed that each $A_i$ is an even integer. Chef wants to buy **exactly two** items of food from the app. ChefEats has a special offer ongoing: when you order two food it