{"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":"告诉你三个关于树的参数n,d,h。\u003cbr\u003e\n其中n为树的节点个数,d为树中任意两点之间的距离的最大值,h是这个树以1作为根节点时,树的高度(也即根节点1到其他节点的距离的最大值)。\u003cbr\u003e\n树中两个节点(x,y)的距离的定义是,从节点x到节点y会经过的边的个数。\u003cbr\u003e\n现在请你输出满足题意的一棵树,只需输出满足题意的树的n-1条无向边即可。\u003cbr\u003e"}},{"title":"Input","value":{"format":"HTML","content":"输入只有一行包含3个整数n,d,h(2\u003c\u003dn\u003c\u003d10^5,1\u003c\u003dh\u003c\u003dd\u003c\u003dn-1).\u003cbr\u003e"}},{"title":"Output","value":{"format":"HTML","content":"如果没有符合要求的树,那么输出-1。\u003cbr\u003e\n否则,请输出n-1行,每行两个整数x,y(1\u003c\u003dx,y\u003c\u003dn),表示第i条无向边连接着x和y这两个节点。"}},{"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\u003e5 3 2\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 2\u003cbr\u003e1 3\u003cbr\u003e3 4\u003cbr\u003e3 5\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\u003e8 5 2\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\u003e-1\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\u003e8 4 2\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\u003e4 8\u003cbr\u003e5 7\u003cbr\u003e2 3\u003cbr\u003e8 1\u003cbr\u003e2 1\u003cbr\u003e5 6\u003cbr\u003e1 5\u003cbr\u003e\u003c/pre\u003e\n \u003c/div\u003e\n\u003c/div\u003e"}}]}