{"trustable":true,"sections":[{"title":"","value":{"format":"HTML","content":"Once upon a time there was a greedy King who ordered his chief Architect to build a wall around the King\u0027s castle. The King was so greedy, that he would not listen to his Architect\u0027s proposals to build a beautiful brick wall with a perfect shape and nice tall towers. Instead, he ordered to build the wall around the whole castle using the least amount of stone and labor, but demanded that the wall should not come closer to the castle than a certain distance. If the King finds that the Architect has used more resources to build the wall than it was absolutely necessary to satisfy those requirements, then the Architect will loose his head. Moreover, he demanded Architect to introduce at once a plan of the wall listing the exact amount of resources that are needed to build the wall.\r\u003cbr\u003e\u003ccenter\u003e\u003cimg src\u003d\"CDN_BASE_URL/795547457e5e67245c9908aff158362e?v\u003d1714111004\"\u003e\u003c/center\u003e\r\u003cbr\u003eYour task is to help poor Architect to save his head, by writing a program that will find the minimum possible length of the wall that he could build around the castle to satisfy King\u0027s requirements.\r\u003cbr\u003e\r\u003cbr\u003eThe task is somewhat simplified by the fact, that the King\u0027s castle has a polygonal shape and is situated on a flat ground. The Architect has already established a Cartesian coordinate system and has precisely measured the coordinates of all castle\u0027s vertices in feet."}},{"title":"Input","value":{"format":"HTML","content":"The first line of the input file contains two integer numbers N and L separated by a space. N (3 \u0026lt;\u003d N \u0026lt;\u003d 1000) is the number of vertices in the King\u0027s castle, and L (1 \u0026lt;\u003d L \u0026lt;\u003d 1000) is the minimal number of feet that King allows for the wall to come close to the castle.\r\u003cbr\u003e\r\u003cbr\u003eNext N lines describe coordinates of castle\u0027s vertices in a clockwise order. Each line contains two integer numbers Xi and Yi separated by a space (-10000 \u0026lt;\u003d Xi, Yi \u0026lt;\u003d 10000) that represent the coordinates of ith vertex. All vertices are different and the sides of the castle do not intersect anywhere except for vertices."}},{"title":"Output","value":{"format":"HTML","content":"Write to the output file the single number that represents the minimal possible length of the wall in feet that could be built around the castle to satisfy King\u0027s requirements. You must present the integer number of feet to the King, because the floating numbers are not invented yet. However, you must round the result in such a way, that it is accurate to 8 inches (1 foot is equal to 12 inches), since the King will not tolerate larger error in the estimates."}},{"title":"Sample","value":{"format":"HTML","content":"\u003ctable class\u003d\u0027vjudge_sample\u0027\u003e\n\u003cthead\u003e\n \u003ctr\u003e\n \u003cth\u003eInput\u003c/th\u003e\n \u003cth\u003eOutput\u003c/th\u003e\n \u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cpre\u003e9 100\r\n200 400\r\n300 400\r\n300 300\r\n400 300\r\n400 400\r\n500 400\r\n500 200\r\n350 200\r\n200 200\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e1628\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}},{"title":"Hint","value":{"format":"HTML","content":"结果四舍五入就可以了"}}]}