Question: OurWay Pizza makes only two kinds of pizza, pepperoni and vegetarian. Any pizza of either kind comes with an even number of breadsticks (not necessarily the same even number for both kinds). Any order of 2 or more pizzas must include at least 1 of each kind. When the delivery driver goes to deliver an order, he or she puts the completed order together by combining 2 suborders-picking up all the pepperoni pizzas from 1 window and all the vegetarian pizzas from another window. Prove that for a delivery of n pizzas, n ≥ 1, there are an even number of breadsticks included.