{"trustable":false,"prependHtml":"\u003cstyle type\u003d\u0027text/css\u0027\u003e\n .input, .output {\n border: 1px solid #888888;\n }\n .output {\n margin-bottom: 1em;\n position: relative;\n top: -1px;\n }\n .output pre, .input pre {\n background-color: #EFEFEF;\n line-height: 1.25em;\n margin: 0;\n padding: 0.25em;\n }\n \u003c/style\u003e\n \u003clink rel\u003d\"stylesheet\" href\u003d\"//codeforces.org/s/96598/css/problem-statement.css\" type\u003d\"text/css\" /\u003e\n\u003cscript\u003e\n window.katexOptions \u003d {\n delimiters: [\n {left: \u0027$$$$$$\u0027, right: \u0027$$$$$$\u0027, display: true},\n {left: \u0027$$$\u0027, right: \u0027$$$\u0027, display: false},\n {left: \u0027$$\u0027, right: \u0027$$\u0027, display: true},\n {left: \u0027$\u0027, right: \u0027$\u0027, display: false}\n ]\n };\n\u003c/script\u003e\n","sections":[{"title":"","value":{"format":"MD","content":"括号匹配是个好问题,大家都爱她。\n\n合法的括号匹配序列被定义为:\n1、空串“”是合法的括号序列\n2、如果“x”和“y”是合法的序列,那么“xy”也是合法的序列\n3、如果“x”是合法的序列,那么“(x)”也是合法的序列\n4、每个合法的括号序列都可以由上面的规则生成\n\n现在,我们有n个字符串,每个字符串只含有\u0027(\u0027和\u0027)\u0027;\n\n我们需要求出,取出任意2个字符串连接后形成正确的括号序列的方案数(每个串都可以重复使用)。"}},{"title":"Input","value":{"format":"MD","content":"第一行一个整数n(1≤n≤300000) \n第二行到第n+1行每行一个字符串\n保证字符串总长度不超过300000;"}},{"title":"Output","value":{"format":"MD","content":"输出合法方案数量"}},{"title":"Examples","value":{"format":"MD","content":"\u003cdiv class\u003d\"sample-test\"\u003e\n \u003cdiv class\u003d\"input\"\u003e\n \u003cdiv class\u003d\"title\"\u003e\n Input\n \u003c/div\u003e\n \u003cpre\u003e3\u003cbr\u003e)\u003cbr\u003e()\u003cbr\u003e(\u003cbr\u003e\u003c/pre\u003e\n \u003c/div\u003e\n \u003cdiv class\u003d\"output\"\u003e\n \u003cdiv class\u003d\"title\"\u003e\n Output\n \u003c/div\u003e\n \u003cpre\u003e2\u003cbr\u003e\u003c/pre\u003e\n \u003c/div\u003e\n \u003cdiv class\u003d\"input\"\u003e\n \u003cdiv class\u003d\"title\"\u003e\n Input\n \u003c/div\u003e\n \u003cpre\u003e2\u003cbr\u003e()\u003cbr\u003e()\u003cbr\u003e\u003c/pre\u003e\n \u003c/div\u003e\n \u003cdiv class\u003d\"output\"\u003e\n \u003cdiv class\u003d\"title\"\u003e\n Output\n \u003c/div\u003e\n \u003cpre\u003e4\u003cbr\u003e\u003c/pre\u003e\n \u003c/div\u003e\n\u003c/div\u003e"}},{"title":"Note","value":{"format":"MD","content":"\u003cp\u003eIn the first example, suitable pairs are $$$(3, 1)$$$ and $$$(2, 2)$$$.\u003c/p\u003e\n\u003cp\u003eIn the second example, any pair is suitable, namely $$$(1, 1), (1, 2), (2, 1), (2, 2)$$$.\u003c/p\u003e"}}]}