{"trustable":true,"sections":[{"title":"","value":{"format":"HTML","content":"\u003cbr\u003eThe\u003cimg src\u003d\"CDN_BASE_URL/bdb75e696e11ca2cb0aaa7c8adbefffe?v\u003d1715827396\" style\u003d\"vertical-align: text-bottom;top: -2.0px;max-width: 100.0%;max-height: 100.0%;\"\u003ecountry has \u003ci\u003eN\u003c/i\u003e cities connected by \u003ci\u003eN\u003c/i\u003e-1 bidirectional roads; one can travel from any city to any other by the roads. One of the biggest trade networks\u003cimg src\u003d\"CDN_BASE_URL/904826917311123f0c1c5068b7b17b09?v\u003d1715827396\" style\u003d\"vertical-align: text-bottom;top: -2.0px;max-width: 100.0%;max-height: 100.0%;\"\u003eis going to build in some cities trade centers selling the main national product. Because building each trade center costs the company a lot of money, they want to build as few of them as possible. Because\u003cimg src\u003d\"CDN_BASE_URL/904826917311123f0c1c5068b7b17b09?v\u003d1715827396\" style\u003d\"vertical-align: text-bottom;top: -2.0px;max-width: 100.0%;max-height: 100.0%;\"\u003eis the biggest producer of the main national product, a citizen living in each city must be able to reach some supermarket using at most \u003ci\u003eK\u003c/i\u003e roads.\u003cbr\u003eYour task is to determine where to build the trade centers.\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 two integers \u003ci\u003eN\u003c/i\u003e and \u003ci\u003eK\u003c/i\u003e (1≤ \u003ci\u003eN\u003c/i\u003e≤ 30000, 1≤ \u003ci\u003eK\u003c/i\u003e≤ 100). Each of the next \u003ci\u003eN\u003c/i\u003e-1 lines contains two integers, denoting the numbers of the cities connected by a road. The cities are numbered starting from 1.\u003cbr\u003e\u003cdiv align\u003d\"left\" style\u003d\"margin-top: 1.0em;\"\u003e\u003cb\u003eOutput\u003c/b\u003e\u003c/div\u003eOutput the number of the trade centers followed by the numbers of the cities where the trade centers should be built.\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\u003e4 1\n1 2\n2 3\n4 2\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e1\n2\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"}}]}