{"trustable":false,"prependHtml":"\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 async src\u003d\"https://mathjax.codeforces.org/MathJax.js?config\u003dTeX-AMS-MML_HTMLorMML\" type\u003d\"text/javascript\"\u003e\u003c/script\u003e","sections":[{"title":"","value":{"format":"HTML","content":"\u003cscript type\u003d\u0027text/x-mathjax-config\u0027\u003eMathJax.Hub.Config({tex2jax: { inlineMath: [[\u0027$\u0027,\u0027$\u0027]] } }); \u003c/script\u003e\n\u003cscript type\u003d\u0027text/javascript\u0027 src\u003d\u0027https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js?config\u003dTeX-AMS-MML_HTMLorMML\u0027\u003e\u003c/script\u003e\n\u003cscript type\u003d\u0027text/javascript\u0027\u003esetTimeout(function(){MathJax.Hub.Queue([\u0027Typeset\u0027, MathJax.Hub, \u0027left_view\u0027]);}, 2000);\u003c/script\u003e\n\u003cdiv class\u003d\"panel_content\"\u003e\n Zero听别人说养牛能致富,于是兴高采烈地从集市上买了一头母牛,这头母牛每年年初会生一头小母牛,而每头小母牛从第四个年头开始,每年年初也生一头小母牛。Zero急切地想知道第n年的时候,自己会有多少头母牛,请你编程帮他一下~\n\u003c/div\u003e"}},{"title":"Input","value":{"format":"HTML","content":"输入数据由多个测试实例组成,每个测试实例占一行,包括一个整数n(0\u0026lt;n\u0026lt;55),n的含义如题目中描述。\n\u003cbr\u003en\u003d0表示输入数据的结束,不做处理。"}},{"title":"Output","value":{"format":"HTML","content":"对于每个测试实例,输出在第n年的时候母牛的数量。\n\u003cbr\u003e每个输出占一行。"}},{"title":"Sample Input","value":{"format":"HTML","content":"\u003cpre\u003e2\n4\n5\n0\u003c/pre\u003e"}},{"title":"Sample Output","value":{"format":"HTML","content":"\u003cpre\u003e2\n4\n6\u003c/pre\u003e"}}]}