{"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":"\u003cdiv class\u003d\"panel_content\"\u003e\n 某宇宙国有N个景区,景区之间有一些双向的路来连接,现在小A想找一条旅游路线,这个路线从x点出发并且最后回到x点,假设经过的路线为V1,V2,....VK,V1,必须满足至除了出发点以外至少要经过2个其他不同的景区,而且不能重复经过同一个景区。现在小A需要你帮他找一条这样的路线,并且花费越少越好。\n \u003cbr\u003e\n\u003c/div\u003e"}},{"title":"Input","value":{"format":"HTML","content":"第一行是2个整数N和M(N \u0026lt;\u003d 100, M \u0026lt;\u003d 1000),代表景区的个数和道路的条数。\n\u003cbr\u003e接下来的M行里,每行包括3个整数a,b,c.代表a和b之间有一条通路,并且需要花费c元(c \u0026lt;\u003d 100)。"}},{"title":"Output","value":{"format":"HTML","content":"对于每个测试实例,如果能找到这样一条路线的话,输出花费的最小值。如果找不到的话,输出\"It\u0027s impossible.\"."}},{"title":"Sample Input","value":{"format":"HTML","content":"\u003cpre\u003e3 3\n1 2 1\n2 3 1\n1 3 1\n3 3\n1 2 1\n1 2 3\n2 3 1\u003c/pre\u003e"}},{"title":"Sample Output","value":{"format":"HTML","content":"\u003cpre\u003e3\nIt\u0027s impossible.\u003c/pre\u003e"}}]}