{"trustable":true,"sections":[{"title":"","value":{"format":"HTML","content":"\u003cimg src\u003d\"https://static.e-olymp.com/content/cc/cc5ac35eb2f57ca4817959d1eec9a2aa0d5ca34b.jpg\" /\u003e\r\n\r\nFrom the childhood little Garik was interested in a question: in how many ways $n$ rooks can be arranged on the chessboard of size $n \\times n$ so that they do not hit each other. He was solving this puzzle for a long time for each case, and when he solved the problem --- he gave up the chess.\r\n\r\nAnd how fast can you solve this puzzle?\r\n\r\n\u003ch2\u003eInput\u003c/h2\u003e\r\nThe size of the chessboard $n~(n \\le 1000)$.\r\n\r\n\u003ch2\u003eOutput\u003c/h2\u003e\r\nPrint the answer, found by Garik."}},{"title":"Example","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\u003e2\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e2\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}}]}