Trick Or Treat

Halloween is approaching, and you plan to distribute sweets to the children visiting your house. You expect a total of $M$ children. You have $N$ boxes of candies and $N$ boxes of chocolates. The $i^{th}$ candy box contains $A_i$ candies, and the $i^{th}$ chocolate box contains $B_i$ chocolates. Your task is to choose **exactly one** box of candies and **exactly one** box of chocolates. You wi