{"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":"你有n双手套,编号1..n,即你一共有2*n只手套,\u003cbr\u003e\n现在这些手套全都放在一个箱子里,你一只一只地拿出来。\u003cbr\u003e\n如果桌子上的手套有和这只手套配对的,则你将其这只手套\u003cbr\u003e\n和桌子上的那只都从桌子上拿走然后给别人。否则,你将这只手套放在桌子上。\u003cbr\u003e\n问你桌子上最多的时候出现了几只手套。"}},{"title":"Input","value":{"format":"HTML","content":"第一行一个整数n(1\u003c\u003dn\u003c\u003d10^5).\u003cbr\u003e\n第二行,按照拿的顺序依次给出2*n个整数,每个整数xi(1\u003c\u003dxi\u003c\u003dn),表示\u003cbr\u003e\n第i次拿出来的手套编号。"}},{"title":"Output","value":{"format":"HTML","content":"一个整数,表示最多的时候,桌子上的手套的个数。"}},{"title":"Example","value":{"format":"HTML","content":"input\u003cbr\u003e\n3\u003cbr\u003e\n2 1 1 3 2 3\u003cbr\u003e\noutput\u003cbr\u003e\n2\u003cbr\u003e"}}]}