{"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":"\u003cdiv\u003e\n \u0026nbsp;\n\u003c/div\u003e \n\u003cdiv\u003e \n \u003cspan\u003e考虑一个有限序列,1\u003c/span\u003e,1,2,1,2,3,1,2,3,4,1,2,3,4,5...这个序列是按照以下的规则生成的:第一个数是1,接下来是1和2,接下来是1,2,\n \u003cspan\u003e3,接下来是1\u003c/span\u003e,2,3,\n \u003cspan\u003e4,等等。例如,第55个数是10。\u003c/span\u003e\n\u003c/div\u003e \n\u003cdiv\u003e\n 现在,给你一个n,求出这个有限序列中第n个数是多少。\n\u003c/div\u003e"}},{"title":"Input","value":{"format":"HTML","content":"\u003cdiv\u003e\n 输入只有一行一个正整数n(1\u0026lt;\u003dn\u0026lt;\u003d10^14)\n \u003cspan\u003e,表示要找的数的位置。\u003c/span\u003e\n\u003c/div\u003e \n\u003cdiv\u003e \n \u003cspan\u003e注意,n较大,所以可能需要使用int64或者long\u003c/span\u003e \n \u003cspan\u003elong。\u003c/span\u003e\n\u003c/div\u003e"}},{"title":"Output","value":{"format":"HTML","content":"\u003cp\u003e \u003cspan\u003e输出序列中第n个位置上的数。\u003c/span\u003e\u003c/p\u003e"}},{"title":"Sample Input","value":{"format":"HTML","content":"\u003cdiv\u003e \n \u003cdiv\u003e \n \u003cdiv\u003e \n \u003cspan\u003e输入样例1:\u003c/span\u003e\n \u003c/div\u003e \n \u003cdiv\u003e\n 2\n \u003c/div\u003e \n \u003cdiv\u003e\n \u0026nbsp;\n \u003c/div\u003e \n \u003cdiv\u003e \n "}},{"title":"Sample Output","value":{"format":"HTML","content":"\u003cdiv\u003e \n \u003cspan\u003e输出样例1\u003c/span\u003e:\n\u003c/div\u003e \n\u003cdiv\u003e\n 1\n\u003c/div\u003e \n\u003cdiv\u003e\n \u0026nbsp;\n\u003c/div\u003e \n\u003cdiv\u003e \n"}}]}