{"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$$\u0027]]\n }\n });\n\u003c/script\u003e\n\u003cscript type\u003d\"text/javascript\" async src\u003d\"https://mathjax.codeforces.org/MathJax.js?config\u003dTeX-AMS_HTML-full\"\u003e\u003c/script\u003e","sections":[{"title":"","value":{"format":"HTML","content":"\u003cstyle type\u003d\u0027text/css\u0027\u003e .input, .output {border: 1px solid #888888;} .output {margin-bottom:1em;position:relative;top:-1px;} .output pre,.input pre {background-color:#EFEFEF;line-height:1.25em;margin:0;padding:0.25em;} .title {background-color:#FFFFFF;border-bottom: 1px solid #888888;font-family:arial;font-weight:bold;padding:0.25em;} \u003c/style\u003e \u003cscript type\u003d\"text/x-mathjax-config\"\u003e\n MathJax.Hub.Config({\n tex2jax: {inlineMath: [[\u0027$$$\u0027,\u0027$$$\u0027]], displayMath: [[\u0027$$$$$$\u0027,\u0027$$$$$$\u0027]]}\n });\n \u003c/script\u003e\n \u003cscript type\u003d\"text/javascript\" async\n src\u003d\"https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js?config\u003dTeX-AMS-MML_HTMLorMML\"\u003e\n \u003c/script\u003e\n\u003cp\u003e故事发生在三国年代。这天下午曹操与周瑜要进行赤壁大战。\u003c/p\u003e\n\u003cp\u003e他们各带领了一支军队,每支军队由n名士兵组成(n为偶数)。每个战斗回合,任意一个存活的士兵可以选择杀死对方的一个士兵,但是每个士兵的选择是同时进行,所以可能存在多个士兵选择杀死同一个士兵的情况。\u003c/p\u003e\n\u003cp\u003e“赤壁之战”包含三个回合:首先是曹操的士兵选择杀周瑜的士兵,之后是周瑜的士兵选择杀曹操的士兵,最后还是曹操的士兵杀周瑜的士兵。\u003c/p\u003e\n\u003cp\u003e现在你需要计算在“赤壁之战”中可能被杀死的最大士兵总数。\u003c/p\u003e"}},{"title":"Input","value":{"format":"HTML","content":"\u003cp\u003e输入包含一个整数n(2 \u003c\u003d n \u003c\u003d 1e8, n为偶数),在战斗开始前,场上一共有2n名士兵。\u003c/p\u003e"}},{"title":"Output","value":{"format":"HTML","content":"\u003cp\u003e输出一个整数,表示在“无人生还”三个过程中最多可以击杀的士兵总数。\u003c/p\u003e"}},{"title":"Examples","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\u003e2\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\u003e3\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\u003e4\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\u003e6\u003cbr\u003e\u003c/pre\u003e\n \u003c/div\u003e\n\u003c/div\u003e"}},{"title":"Note","value":{"format":"HTML","content":"\u003cp\u003e在第一个测试样例中:\u003c/p\u003e\n\u003cp\u003e1) 曹操的士兵1和2向周瑜的士兵1开枪。\u003c/p\u003e\n\u003cp\u003e2) 周瑜的士兵2向曹操的士兵1开枪。\u003c/p\u003e\n\u003cp\u003e3) 曹操的士兵2向周瑜的士兵2开枪。\u003c/p\u003e\n\u003cp\u003e最终共有三名士兵被击杀:曹操的士兵1和周瑜的士兵1、士兵2。\u003c/p\u003e"}}]}