{"trustable":true,"prependHtml":"\u003cstyle type\u003d\"text/css\"\u003e\n #problem-body \u003e pre {\n display: block;\n padding: 9.5px;\n margin: 0 0 10px;\n font-size: 13px;\n line-height: 1.42857143;\n word-break: break-all;\n word-wrap: break-word;\n color: #333;\n background: rgba(255, 255, 255, 0.5);\n border: 1px solid #ccc;\n border-radius: 6px;\n }\n\u003c/style\u003e\n","sections":[{"title":"","value":{"format":"HTML","content":"\u003cdiv id\u003d\"problem-body\"\u003e\n\t\u003cp\u003eThis time I will not bore you with a long and boring sentence. Give a connected graph, you must find all the edges that are critical, in other words you must find the edges which when removed divide the graph.\u003c/p\u003e\r\n\u003ch3\u003eInput\u003c/h3\u003e\r\n\u003cp\u003eThe first line contains a integer \u003cstrong\u003eNC\u003c/strong\u003e (1 ≤ NC ≤ 200), the number of test cases. Then follow NC test cases.\u003c/p\u003e\r\n\u003cp\u003eEach case begins with two integers \u003cstrong\u003eN\u003c/strong\u003e (1 ≤ N ≤ 700) and \u003cstrong\u003eM\u003c/strong\u003e (N-1 ≤ M ≤ N * (N-1) / 2), the number of nodes and the number of edges respectively. Then follow M lines, each with a pair of integers \u003cstrong\u003ea b\u003c/strong\u003e (1 ≤ a, b ≤ N) indicate that between the node \u003cstrong\u003ea\u003c/strong\u003e and the node \u003cstrong\u003eb\u003c/strong\u003e there is a edge.\u003c/p\u003e\r\n\u003ch3\u003eOutput\u003c/h3\u003e\r\n\u003cp\u003eFor each test case print the list of ways to protect the following format:\u003c/p\u003e\r\n\u003cpre\u003e\r\n Caso #n\r\n t\r\n x1 y2\r\n x2 y2\r\n ...\r\n xt yt\u003c/pre\u003e\r\n\u003cp\u003eWhere \u003cstrong\u003en\u003c/strong\u003e is the case number (starting from 1), \u003cstrong\u003et\u003c/strong\u003e is the total of critical edges, list elements \u003cstrong\u003ex\u003csub\u003ei\u003c/sub\u003e \u0026nbsp;y\u003csub\u003ei\u003c/sub\u003e\u003c/strong\u003e indicates, for each line, there is a critical edge between the node x\u003csub\u003ei\u003c/sub\u003e and node y\u003csub\u003ei\u003c/sub\u003e (1 ≤ x\u003csub\u003ei\u003c/sub\u003e \u003cy\u003e\u003csub\u003ei\u003c/sub\u003e ≤ N). In addition, the list should be sorted in non-decreasing order first by \u003cstrong\u003ex\u003csub\u003ei\u003c/sub\u003e\u003c/strong\u003e and then by \u003cstrong\u003ey\u003csub\u003ei\u003c/sub\u003e\u003c/strong\u003e. Also\u0026nbsp;\u003cstrong\u003ex\u003csub\u003ei\u003c/sub\u003e\u0026nbsp;\u0026lt; y\u003csub\u003ei\u003c/sub\u003e\u003c/strong\u003e\u0026nbsp;must hold.\u003c/y\u003e\u003c/p\u003e\r\n\u003cp\u003eIf there isn\u0027t any critical edge print: \"Sin bloqueos\" (quotes for clarity).\u003c/p\u003e\r\n\u003ch3\u003eExample\u003c/h3\u003e\r\n\u003cdiv\u003e\u003ctable class\u003d\"vjudge_sample\"\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\u003e3\r\n5 4\r\n1 2\r\n4 2\r\n2 3\r\n4 5\r\n5 5\r\n1 2\r\n1 3\r\n3 2\r\n3 4\r\n5 4\r\n4 6\r\n1 3\r\n1 4\r\n2 1\r\n3 2\r\n4 2\r\n4 3\r\n\r\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003eCaso #1\r\n4\r\n1 2\r\n2 3\r\n2 4\r\n4 5\r\nCaso #2\r\n2\r\n3 4\r\n4 5\r\nCaso #3\r\nSin bloqueos\r\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\r\n\n\u003c/div\u003e"}}]}