{"trustable":true,"prependHtml":"\u003cscript\u003e window.katexOptions \u003d { disable: true }; \u003c/script\u003e\n\u003cscript type\u003d\"text/x-mathjax-config\"\u003e\n MathJax.Hub.Config({\n tex2jax: {\n inlineMath: [[\u0027$$$\u0027,\u0027$$$\u0027], [\u0027$\u0027,\u0027$\u0027]],\n displayMath: [[\u0027$$$$$$\u0027,\u0027$$$$$$\u0027], [\u0027$$\u0027,\u0027$$\u0027]]\n }\n });\n\u003c/script\u003e\n\u003cscript async src\u003d\"https://mathjax.codeforces.org/MathJax.js?config\u003dTeX-AMS-MML_HTMLorMML\" type\u003d\"text/javascript\"\u003e\u003c/script\u003e","sections":[{"title":"","value":{"format":"HTML","content":"\u003cdiv class\u003d\"panel_content\"\u003e Let A be an integral series {A\u003csub\u003e1\u003c/sub\u003e, A\u003csub\u003e2\u003c/sub\u003e, . . . , A\u003csub\u003en\u003c/sub\u003e}.\u003cbr\u003e\u003cbr\u003e The zero-order series of A is A itself.\u003cbr\u003e\u003cbr\u003e The first-order series of A is {B\u003csub\u003e1\u003c/sub\u003e, B\u003csub\u003e2\u003c/sub\u003e, . . . , B\u003csub\u003en-1\u003c/sub\u003e},where B\u003csub\u003ei\u003c/sub\u003e \u003d A\u003csub\u003ei+1\u003c/sub\u003e - A\u003csub\u003ei\u003c/sub\u003e.\u003cbr\u003e\u003cbr\u003e The ith-order series of A is the first-order series of its (i - 1)th-order series (2\u0026lt;\u003di\u0026lt;\u003dn - 1).\u003cbr\u003e\u003cbr\u003e Obviously, the (n - 1)th-order series of A is a single integer. Given A, figure out that integer.\u003c/div\u003e"}},{"title":"Input","value":{"format":"HTML","content":" The input consists of several test cases. The first line of input gives the number of test cases T (T\u0026lt;\u003d10).\u003cbr\u003e\u003cbr\u003eFor each test case:\u003cbr\u003e The first line contains a single integer n(1\u0026lt;\u003dn\u0026lt;\u003d3000), which denotes the length of series A.\u003cbr\u003e The second line consists of n integers, describing A\u003csub\u003e1\u003c/sub\u003e, A\u003csub\u003e2\u003c/sub\u003e, . . . , A\u003csub\u003en\u003c/sub\u003e. (0\u0026lt;\u003dA\u003csub\u003ei\u003c/sub\u003e\u0026lt;\u003d10\u003csup\u003e5\u003c/sup\u003e)\u003cbr\u003e"}},{"title":"Output","value":{"format":"HTML","content":" For each test case, output the required integer in a line."}},{"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\u003e2\r\n3\r\n1 2 3\r\n4\r\n1 5 7 2\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e0\r\n-5\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}}]}