{"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":"\u003cp\u003eTừ bản hit \"Creep\" của Đầu-đài, chúng ta biết rằng Thom Yorke là một \"weirdo\". Ông ta không hài lòng với một số thứ, đặc biệt là thứ tự của các số tự nhiên. Ông ta quyết định sửa lại thứ tự của chúng, nhưng vì có rất nhiều số tự nhiên nên Thom quyết định xử lí \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003en\u003c/i\u003e\u003c/span\u003e số tự nhiên đầu. Ông ta viết dãy số lại như sau: đầu tiên \n viết các số lẻ từ và đánh dấu từ \u003cspan class\u003d\"tex-span\"\u003e1\u003c/span\u003e tới \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003en\u003c/i\u003e\u003c/span\u003e (tăng dần), sau đó là các số chẵn và đánh dấu từ \u003cspan class\u003d\"tex-span\"\u003en \u003c/span\u003e to \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003e2n\u003c/i\u003e\u003c/span\u003e (tất nhiên là tăng dần). Hãy giúp Thom Yorke tìm xem số nào có vị trí \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003ek\u003c/i\u003e\u003c/span\u003e.\u003c/p\u003e\n\u003cp\u003eVí dụ như \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003en \u003d 6\u003c/i\u003e\u003c/span\u003e thì dãy số đó là {\u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003e1; 3; 5; 2; 4; 6\u003c/i\u003e\u003c/span\u003e}. Số ở vị trí 3 là 5.\n\u003cp\u003e \u003c/p\u003e\n \u003cimg src\u003d\"https://i.ytimg.com/vi/XFkzRNyygfk/maxresdefault.jpg\" \u003e\n"}},{"title":"Input","value":{"format":"HTML","content":"\u003cp\u003eMột dòng duy nhất chứa hai số nguyên \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003en\u003c/i\u003e\u003c/span\u003e và \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003ek\u003c/i\u003e\u003c/span\u003e (\u003cspan class\u003d\"tex-span\"\u003e1 ≤ \u003ci\u003ek\u003c/i\u003e ≤ \u003ci\u003en\u003c/i\u003e ≤ 10\u003csup class\u003d\"upper-index\"\u003e12\u003c/sup\u003e\u003c/span\u003e).\u003c/p\u003e"}},{"title":"Output","value":{"format":"HTML","content":"\u003cp\u003eIn ra số tự nhiên nằm ở vị trí \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003ek\u003c/i\u003e\u003c/span\u003e.\u003c/p\u003e"}},{"title":"Sample 1","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\u003e10 3\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e5\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}},{"title":"Sample 2","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\u003e7 7\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e6\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}}]}