{"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\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 type\u003d\"text/javascript\" async src\u003d\"https://mathjax.codeforces.org/MathJax.js?config\u003dTeX-AMS_HTML-full\"\u003e\u003c/script\u003e","sections":[{"title":"","value":{"format":"HTML","content":"\u003cpre\u003e\n给定一颗无向的树。\n你需要在这棵树中找到三个两两不相同的顶点a,b,c。\n使得a与b,a与c,b与c之间的这三条最短路径所经过的所有边(重复经过的边只算一次)的数量最大。\n(结合样例作图理解)\n\u003cpre\u003e"}},{"title":"Input","value":{"format":"HTML","content":"\u003cpre\u003e\n第一行为整数n,代表这棵树的点的个数。(3\u003c\u003dn\u003c\u003d2e5)\n接下来为n-1行,代表n-1条边。\n每行两个整数a和b,代表a点和b点之间有一条边。(顶点用1-n的整数标记)\n\u003cpre\u003e"}},{"title":"Output","value":{"format":"HTML","content":"\u003cpre\u003e\n输出两行。\n第一行输出边的最大数量为多少。\n第二行输出选择的三个两两不相同的顶点。如果有多种答案,输出任意一种。\n\u003cpre\u003e"}},{"title":"Example","value":{"format":"HTML","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\u003e8\n1 3\n3 4\n3 2\n2 6\n2 5\n2 7\n7 8\n\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\u003e5\n4 6 8\n\u003c/pre\u003e\n \u003c/div\u003e\n\u003c/div\u003e"}},{"title":"Note","value":{"format":"HTML","content":"\u003cpre\u003e\n样例也可以选择1,4,8这三个点。\n两两之间的三条最短路径经过的五条边为\n1-3\n3-4\n3-2\n2-7\n7-8\n\u003cpre\u003e"}}]}