{"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$$\u0027, display: true},\n {left: \u0027$\u0027, right: \u0027$\u0027, display: false}\n ]\n };\n\u003c/script\u003e\n","sections":[{"title":"","value":{"format":"HTML","content":"\u003cstyle type\u003d\u0027text/css\u0027\u003e .input, .output {border: 1px solid #888888;} .output {margin-bottom:1em;position:relative;top:-1px;} .output pre,.input pre {background-color:#EFEFEF;line-height:1.25em;margin:0;padding:0.25em;} .title {background-color:#FFFFFF;border-bottom: 1px solid #888888;font-family:arial;font-weight:bold;padding:0.25em;} \u003c/style\u003e \u003cscript type\u003d\"text/x-mathjax-config\"\u003e\n MathJax.Hub.Config({\n tex2jax: {inlineMath: [[\u0027$$$\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\u003edaffodil likes to keep things in their place.\u003c/p\u003e\n\u003cp\u003eToday he faced a problem to put his socks in the wardrobe. He has \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003en\u003c/i\u003e\u003c/span\u003e distinct pairs of socks which are initially in a bag. The pairs are numbered from \u003cspan class\u003d\"tex-span\"\u003e1\u003c/span\u003e to \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003en\u003c/i\u003e\u003c/span\u003e. daffodil wants to put paired socks together and put them in the wardrobe. He takes the socks one by one from the bag, and for each sock he looks whether the pair of this sock has been already took out of the bag, or not. If not (that means the pair of this sock is still in the bag), he puts the current socks on the table in front of him. Otherwise, he puts both socks from the pair to the wardrobe.\u003c/p\u003e\n\u003cp\u003edaffodil remembers the order in which he took the socks from the bag. Can you tell him what is the maximum number of socks that were on the table at the same time? \u003c/p\u003e"}},{"title":"Input","value":{"format":"HTML","content":"\u003cp\u003eThe first line contains the single integer \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003en\u003c/i\u003e\u003c/span\u003e (\u003cspan class\u003d\"tex-span\"\u003e1 ≤ \u003ci\u003en\u003c/i\u003e ≤ 10\u003csup class\u003d\"upper-index\"\u003e5\u003c/sup\u003e\u003c/span\u003e)\u0026nbsp;— the number of sock pairs.\u003c/p\u003e\n\u003cp\u003eThe second line contains \u003cspan class\u003d\"tex-span\"\u003e2\u003ci\u003en\u003c/i\u003e\u003c/span\u003e integers \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003ex\u003c/i\u003e\u003csub class\u003d\"lower-index\"\u003e1\u003c/sub\u003e, \u003ci\u003ex\u003c/i\u003e\u003csub class\u003d\"lower-index\"\u003e2\u003c/sub\u003e, ..., \u003ci\u003ex\u003c/i\u003e\u003csub class\u003d\"lower-index\"\u003e2\u003ci\u003en\u003c/i\u003e\u003c/sub\u003e\u003c/span\u003e (\u003cspan class\u003d\"tex-span\"\u003e1 ≤ \u003ci\u003ex\u003c/i\u003e\u003csub class\u003d\"lower-index\"\u003e\u003ci\u003ei\u003c/i\u003e\u003c/sub\u003e ≤ \u003ci\u003en\u003c/i\u003e\u003c/span\u003e), which describe the order in which daffodil took the socks from the bag. More precisely, \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003ex\u003c/i\u003e\u003csub class\u003d\"lower-index\"\u003e\u003ci\u003ei\u003c/i\u003e\u003c/sub\u003e\u003c/span\u003e means that the \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003ei\u003c/i\u003e\u003c/span\u003e-th sock daffodil took out was from pair \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003ex\u003c/i\u003e\u003csub class\u003d\"lower-index\"\u003e\u003ci\u003ei\u003c/i\u003e\u003c/sub\u003e\u003c/span\u003e.\u003c/p\u003e\n\u003cp\u003eIt is guaranteed that daffodil took exactly two socks of each pair.\u003c/p\u003e"}},{"title":"Output","value":{"format":"HTML","content":"\u003cp\u003ePrint single integer\u0026nbsp;— the maximum number of socks that were on the table at the same time.\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\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 dafffodil 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 daffodil 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. Daffodil 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. daffodil 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. daffodil 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. daffodil 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. daffodil 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."}}]}