{"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":"HTML","content":"K神是个有秩序的女孩,喜欢把东西放在自己的位置上。\u003cp\u003e\n今天她把袜子放在衣橱里遇到了一个难题。她有N双不同的袜子,最初是在一个袋子里。这对袜子的编号是从1到N。K神想把成对的袜子放在一起,放进衣柜里。她从袋子里一只接一只地拿出袜子,每只袜子她都要看看这双袜子是否已经从袋子里拿出来了。如果没有(这意味着这双袜子还在包里),她就把现在的袜子放在她前面的桌子上。否则,如果她拿到成对的袜子的话,她就把这双袜子都放到衣柜里。\u003cp\u003e\nK神还记得她从袋子里取出袜子的顺序。你能告诉她桌上同时放的袜子的最大数量是多少吗?\n"}},{"title":"Input","value":{"format":"HTML","content":"第一行包含单个整数n ((1 ≤ n ≤ 100000)-袜子的对的数目。\u003cp\u003e\n第二行包含2*n 整数x1, x2, ..., x2n (1 ≤ xi ≤ n),描述K神从包中取出袜子的顺序。更确切地说,xi 意味着K神的第i 次取出的袜子是什么。\n"}},{"title":"Output","value":{"format":"HTML","content":"输出桌子上最大的袜子数"}},{"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\u003e1\u003cbr\u003e1 1\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\u003e1\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\u003e3\u003cbr\u003e2 1 1 3 2 3\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\u003c/div\u003e"}},{"title":"Note","value":{"format":"HTML","content":"\u003cp\u003eIn the first example Andryusha took a sock from the first pair and put it on the table. Then he took the next sock which is from the first pair as well, so he immediately puts both socks to the wardrobe. Thus, at most one sock was on the table at the same time.\u003c/p\u003e\n\u003cp\u003eIn the second example Andryusha behaved as follows: \u003c/p\u003e\n\u003cul\u003e \n \u003cli\u003e Initially the table was empty, he took out a sock from pair \u003cspan class\u003d\"tex-span\"\u003e2\u003c/span\u003e and put it on the table. \u003c/li\u003e\n \u003cli\u003e Sock \u003cspan class\u003d\"tex-span\"\u003e(2)\u003c/span\u003e was on the table. Andryusha took out a sock from pair \u003cspan class\u003d\"tex-span\"\u003e1\u003c/span\u003e and put it on the table. \u003c/li\u003e\n \u003cli\u003e Socks \u003cspan class\u003d\"tex-span\"\u003e(1, 2)\u003c/span\u003e were on the table. Andryusha took out a sock from pair \u003cspan class\u003d\"tex-span\"\u003e1\u003c/span\u003e, and put this pair into the wardrobe. \u003c/li\u003e\n \u003cli\u003e Sock \u003cspan class\u003d\"tex-span\"\u003e(2)\u003c/span\u003e was on the table. Andryusha took out a sock from pair \u003cspan class\u003d\"tex-span\"\u003e3\u003c/span\u003e and put it on the table. \u003c/li\u003e\n \u003cli\u003e Socks \u003cspan class\u003d\"tex-span\"\u003e(2, 3)\u003c/span\u003e were on the table. Andryusha took out a sock from pair \u003cspan class\u003d\"tex-span\"\u003e2\u003c/span\u003e, and put this pair into the wardrobe. \u003c/li\u003e\n \u003cli\u003e Sock \u003cspan class\u003d\"tex-span\"\u003e(3)\u003c/span\u003e was on the table. Andryusha took out a sock from pair \u003cspan class\u003d\"tex-span\"\u003e3\u003c/span\u003e and put this pair into the wardrobe. \u003c/li\u003e\n\u003c/ul\u003e Thus, at most two socks were on the table at the same time."}}]}