Chef and Coupon

Chef wants to order food from a food delivery app. He wishes to order once today, and buy three items costing $A_1, A_2$ and $A_3$ rupees, respectively. He'll also order once tomorrow, when he'll buy three items costing $B_1, B_2$ and $B_3$ rupees, respectively. There is an additional delivery charge of rupees $D$ for each order. He notices that there is a coupon on sale, which costs rupees $C$.