P3020 [USACO11MAR] Package Delivery S

Farmer John must deliver a package to Farmer Dan, and is preparing to make his journey. To keep the peace, he gives a tasty treat to every cow that he meets along his way and, of course, FJ is so frugal that he would like to encounter as few cows as possible. 农夫约翰必须送一个包裹给农夫丹，并准备去旅行。为了保持和平，他必须给每一头遇到的奶牛一些吃的，当然，FJ很节俭，他想可能遇到尽可能少的奶牛。 FJ has plotted a map of N (1

无

无