{"trustable":true,"sections":[{"title":"","value":{"format":"HTML","content":"\u003cbr\u003eThe ancient race of\u003cimg src\u003d\"CDN_BASE_URL/0d2fe2dd311a59684dfc02abafa5d9e1?v\u003d1715803106\" style\u003d\"vertical-align: text-bottom;top: -2.0px;max-width: 100.0%;max-height: 100.0%;\"\u003ehas built \u003ci\u003eN\u003c/i\u003e cities connected with two-way roads. They believed in magic of an even number \u003ci\u003eK\u003c/i\u003e and built the roads in such a way that each city had exactly \u003ci\u003eK\u003c/i\u003e roads going from it.\u003cbr\u003eThe Hollars decided to decorate some roads because of their religious holiday. Because they also believe in magic of an even number 2, each city must have exactly 2 decorated roads going from it.\u003cbr\u003eYou have to find the roads needing to be decorated.\u003cbr\u003e\u003cdiv align\u003d\"left\" style\u003d\"margin-top: 1.0em;\"\u003e\u003cb\u003eInput\u003c/b\u003e\u003c/div\u003eThe first line of the input contains integers \u003ci\u003eN\u003c/i\u003e and \u003ci\u003eK\u003c/i\u003e (2≤ \u003ci\u003eK\u003c/i\u003e\u003ci\u003eNK\u003c/i\u003e/2 lines contains description of one road, being the numbers of the cities connected by this road. The cities are numbered starting from 1. There is no road from a city to itself; each pair of cities is connected by at most one road.\u003cbr\u003e\u003cdiv align\u003d\"left\" style\u003d\"margin-top: 1.0em;\"\u003e\u003cb\u003eOutput\u003c/b\u003e\u003c/div\u003eIf it is impossible to decorate the roads, the only line of the output must contain \u0027NO\u0027 (without quotes). Otherwise the first line of the output must contain \u0027YES\u0027 (without quotes); the rest of the output must contain \u003ci\u003eN\u003c/i\u003e lines, each containing one number of a road to be decorated. The roads are numbered starting from 1 in the same order as they appear in the input.\u003cbr\u003e"}},{"title":"Sample 1","value":{"format":"HTML","content":"\u003ctable class\u003d\u0027vjudge_sample\u0027\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\u003e9 4\n1 2\n1 3\n1 4\n1 5\n2 3\n3 4\n4 5\n5 2\n2 6\n3 7\n4 8\n5 9\n6 7\n7 8\n8 9\n9 6\n7 9\n8 6\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003eYES\n4\n9\n5\n3\n12\n13\n10\n11\n15\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}},{"title":"","value":{"format":"HTML","content":"\u003cbr\u003e\n Novosibirsk SU Contest #2, by Novosibirsk Team #1"}}]}