{"trustable":false,"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":"\u003cp\u003e房间里一共有10000000个人,你想选择其中的一些人跟你一起完成任务。\u003c/p\u003e\n\u003cp\u003e但是有一些限制,假设你选择了房间中的k个人,那么这k个人中的任何两个人都必须有直接或者间接的朋友关系。\u003c/p\u003e\n\u003cp\u003e你觉得人越多越好,请问你最多能选择多少人?\u003c/p\u003e"}},{"title":"Input","value":{"format":"HTML","content":"输入的第一行包含整数 n (0 ≤ n ≤ 100 000) - 表示有n个朋友关系. 以下n行各包含一对数字A和B,用一个空格隔开,表示A和B是朋友。(A ≠ B, 1 ≤ A, B ≤ 10000000)"}},{"title":"Output","value":{"format":"HTML","content":"输出你最多能选择多少人\u003cbr\u003e"}},{"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\u003e\u003cpre\u003e4\n1 2\n3 4\n5 6\n1 6\n4\n1 2\n3 4\n5 6\n7 8\n\u003c/pre\u003e\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e\u003cpre\u003e4\n2\n\u003c/pre\u003e\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":"\u003cbr\u003eA and B are friends(direct or indirect), B and C are friends(direct or indirect), \u003cbr\u003ethen A and C are also friends(indirect).\u003cbr\u003e\u003cbr\u003e In the first sample {1,2,5,6} is the result.\u003cbr\u003eIn the second sample {1,2},{3,4},{5,6},{7,8} are four kinds of answers.\u003cbr\u003e"}}]}