discount 3 while if elif else True

finished = False
while finished == False :
    print("Hi, I am Marvin, your personal bot.")
    command = input("How can I help? ")
    if command == "calculate a discount for my basket":
        shopping = []
        R1 = input ( "How many items are in your basket ? ")
        save = 0
        for item_number in range(int(R1)):
            item = input ( "What is the item " + str(item_number+1) + "  you wish to buy ? " )
            shopping.append(item)
            cost1= input ( "What is the list price of the item "  + str(item_number+1) + "  you wish to buy today ? " )
            cost_off = input( " What is the percentage discount for item " + str(item_number+1) + "?" )
            save = save + int(cost1)*(int(cost_off)/100)



        print ( "You will save  " + str(save) + " RMB. " )
    elif command == "bye" :
        finished = True
    else :
        print ("Sorry I do not understand this " )