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문제

세종이는 행성이 n개 있는 태양계의 왕이다. 행성 수가 너무 많아서 이름을 일일이 붙이는 것은 포기한 지 오래고, 대신 1~n의 구분되는 번호로 표기한다. 세종이의 집은 1번 행성에, PC방은 2번 행성에 위치한다. 또한 세종이는 고대부터 그 누구보다도 빠르게 PC방으로 달려가 핫타임을 놓치지 않기 위해 1번, 2번 행성을 왕래하게 해 주는 전용 비밀 양방향 텔레포터를 마련하고 있었으며, 한 번 이동하는 데 250분이 걸린다.

시대가 발전하여 각 행성들 사이에 교통을 위한 텔레포터가 많이 생겼다. 각각의 텔레포터는 양방향이고 이동에 정확히 한 시간이 걸린다. 행성의 시민들은 행성경제 활성화를 위하여 더 많은 텔레포터를 설치해줄 것을 세종이에게 부탁하였다.

세종이는 성군이 되기 위해 최대한 많은 부탁을 들어주려고 하지만, 단 한 가지는 용납할 수 없다. 텔레포터가 추가로 설치되다가 1번, 2번 행성 사이의 이동 시간이 자신의 비밀 텔레포터를 사용한 것, 즉 250분보다 빨라지는 것이다. 그러면 세종이가 핫타임 이벤트에 참가하기 위해 PC방 자리를 잡는 것에 차질이 생길지도 모른다.

따라서 세종이는 1번, 2번 행성을 교통 텔레포터들을 사용해 왕래하는 데 항상 250분보다 많은 시간이 들게 하면서 태양계에 최대한 많은 텔레포터를 설치하고 싶다. 몇 개의 텔레포터를 설치할 수 있을까? 물론 동일한 행성 쌍 사이에 여러 개의 텔레포터를 설치하는 건 무의미하기 때문에 그런 행동은 피할 것이다. 세종이가 그런 무의미한 곳에 비용을 들일 바에 차라리 자기 캐릭터에 현질을 하는 게 이득이다.

입력

첫째 줄에 행성 수 n과 이미 설치된 교통 텔레포터 수 m이 주어진다. (2 ≤ n ≤ 40,000, 0 ≤ m ≤ 1,000,000)

둘째 줄부터 m개의 줄에 걸쳐 기존의 각 텔레포터가 연결한 서로 다른 두 행성의 번호가 주어진다. 각 번호는 1 이상 n 이하의 정수이다. 여기엔 세종이의 전용 텔레포터는 포함되어 있지 않다. 같은 곳을 연결하는 텔레포터가 2번 이상 등장하지 않는다.

기존에 연결된 텔레포터만을 가지고는 어떠한 경로를 거치더라도 1번 행성과 2번 행성 사이를 250분 미만의 시간으로 왕래할 수 없음이 보장된다. 물론 그 이상이 시간으로 왕래가 가능할 수는 있다.

출력

첫째 줄에 추가로 건설할 수 있는 텔레포터 개수의 최댓값을 출력한다.

예제 입력 1

10 10
1 3
3 5
5 7
7 9
2 9
1 4
4 6
6 8
8 10
2 10

예제 출력 1

10

힌트

예제를 그림으로 나타낸 것이다. 실선이 이미 연결된 텔레포터이며 점선이 최대한 더 지을 수 있는 텔레포터들을 나타낸 것이다.

[{"problem_id":"8193","problem_lang":"0","title":"\ud0b9\uc138\uc885","description":"<p>\uc138\uc885\uc774\ub294 \ud589\uc131\uc774 n\uac1c \uc788\ub294 \ud0dc\uc591\uacc4\uc758 \uc655\uc774\ub2e4. \ud589\uc131 \uc218\uac00 \ub108\ubb34 \ub9ce\uc544\uc11c \uc774\ub984\uc744 \uc77c\uc77c\uc774 \ubd99\uc774\ub294 \uac83\uc740 \ud3ec\uae30\ud55c \uc9c0 \uc624\ub798\uace0, \ub300\uc2e0 1~n\uc758 \uad6c\ubd84\ub418\ub294 \ubc88\ud638\ub85c \ud45c\uae30\ud55c\ub2e4. \uc138\uc885\uc774\uc758 \uc9d1\uc740 1\ubc88 \ud589\uc131\uc5d0, PC\ubc29\uc740 2\ubc88 \ud589\uc131\uc5d0 \uc704\uce58\ud55c\ub2e4. \ub610\ud55c \uc138\uc885\uc774\ub294 \uace0\ub300\ubd80\ud130 \uadf8 \ub204\uad6c\ubcf4\ub2e4\ub3c4 \ube60\ub974\uac8c PC\ubc29\uc73c\ub85c \ub2ec\ub824\uac00 \ud56b\ud0c0\uc784\uc744 \ub193\uce58\uc9c0 \uc54a\uae30 \uc704\ud574 1\ubc88, 2\ubc88 \ud589\uc131\uc744 \uc655\ub798\ud558\uac8c \ud574 \uc8fc\ub294 \uc804\uc6a9 \ube44\ubc00 \uc591\ubc29\ud5a5 \ud154\ub808\ud3ec\ud130\ub97c \ub9c8\ub828\ud558\uace0 \uc788\uc5c8\uc73c\uba70, \ud55c \ubc88 \uc774\ub3d9\ud558\ub294 \ub370 250\ubd84\uc774 \uac78\ub9b0\ub2e4.<\/p>\r\n\r\n<p>\uc2dc\ub300\uac00 \ubc1c\uc804\ud558\uc5ec \uac01 \ud589\uc131\ub4e4 \uc0ac\uc774\uc5d0 \uad50\ud1b5\uc744 \uc704\ud55c \ud154\ub808\ud3ec\ud130\uac00 \ub9ce\uc774 \uc0dd\uacbc\ub2e4. \uac01\uac01\uc758 \ud154\ub808\ud3ec\ud130\ub294 \uc591\ubc29\ud5a5\uc774\uace0 \uc774\ub3d9\uc5d0 \uc815\ud655\ud788 \ud55c \uc2dc\uac04\uc774 \uac78\ub9b0\ub2e4. \ud589\uc131\uc758 \uc2dc\ubbfc\ub4e4\uc740 \ud589\uc131\uacbd\uc81c \ud65c\uc131\ud654\ub97c \uc704\ud558\uc5ec \ub354 \ub9ce\uc740 \ud154\ub808\ud3ec\ud130\ub97c \uc124\uce58\ud574\uc904 \uac83\uc744 \uc138\uc885\uc774\uc5d0\uac8c \ubd80\ud0c1\ud558\uc600\ub2e4.<\/p>\r\n\r\n<p>\uc138\uc885\uc774\ub294 \uc131\uad70\uc774 \ub418\uae30 \uc704\ud574 \ucd5c\ub300\ud55c \ub9ce\uc740 \ubd80\ud0c1\uc744 \ub4e4\uc5b4\uc8fc\ub824\uace0 \ud558\uc9c0\ub9cc, \ub2e8 \ud55c \uac00\uc9c0\ub294 \uc6a9\ub0a9\ud560 \uc218 \uc5c6\ub2e4. \ud154\ub808\ud3ec\ud130\uac00 \ucd94\uac00\ub85c \uc124\uce58\ub418\ub2e4\uac00 1\ubc88, 2\ubc88 \ud589\uc131 \uc0ac\uc774\uc758 \uc774\ub3d9 \uc2dc\uac04\uc774 \uc790\uc2e0\uc758 \ube44\ubc00 \ud154\ub808\ud3ec\ud130\ub97c \uc0ac\uc6a9\ud55c \uac83, \uc989 250\ubd84\ubcf4\ub2e4 \ube68\ub77c\uc9c0\ub294 \uac83\uc774\ub2e4. \uadf8\ub7ec\uba74 \uc138\uc885\uc774\uac00 \ud56b\ud0c0\uc784 \uc774\ubca4\ud2b8\uc5d0 \ucc38\uac00\ud558\uae30 \uc704\ud574 PC\ubc29 \uc790\ub9ac\ub97c \uc7a1\ub294 \uac83\uc5d0 \ucc28\uc9c8\uc774 \uc0dd\uae38\uc9c0\ub3c4 \ubaa8\ub978\ub2e4.<\/p>\r\n\r\n<p>\ub530\ub77c\uc11c \uc138\uc885\uc774\ub294 1\ubc88, 2\ubc88 \ud589\uc131\uc744 \uad50\ud1b5 \ud154\ub808\ud3ec\ud130\ub4e4\uc744 \uc0ac\uc6a9\ud574 \uc655\ub798\ud558\ub294 \ub370 \ud56d\uc0c1 250\ubd84\ubcf4\ub2e4 \ub9ce\uc740 \uc2dc\uac04\uc774 \ub4e4\uac8c \ud558\uba74\uc11c \ud0dc\uc591\uacc4\uc5d0 \ucd5c\ub300\ud55c \ub9ce\uc740 \ud154\ub808\ud3ec\ud130\ub97c \uc124\uce58\ud558\uace0 \uc2f6\ub2e4. \uba87 \uac1c\uc758 \ud154\ub808\ud3ec\ud130\ub97c \uc124\uce58\ud560 \uc218 \uc788\uc744\uae4c? \ubb3c\ub860 \ub3d9\uc77c\ud55c \ud589\uc131 \uc30d \uc0ac\uc774\uc5d0 \uc5ec\ub7ec \uac1c\uc758 \ud154\ub808\ud3ec\ud130\ub97c \uc124\uce58\ud558\ub294 \uac74 \ubb34\uc758\ubbf8\ud558\uae30 \ub54c\ubb38\uc5d0 \uadf8\ub7f0 \ud589\ub3d9\uc740 \ud53c\ud560 \uac83\uc774\ub2e4. \uc138\uc885\uc774\uac00 \uadf8\ub7f0 \ubb34\uc758\ubbf8\ud55c \uacf3\uc5d0 \ube44\uc6a9\uc744 \ub4e4\uc77c \ubc14\uc5d0 \ucc28\ub77c\ub9ac \uc790\uae30 \uce90\ub9ad\ud130\uc5d0 \ud604\uc9c8\uc744 \ud558\ub294 \uac8c \uc774\ub4dd\uc774\ub2e4.<\/p>\r\n","input":"<p>\uccab\uc9f8 \uc904\uc5d0 \ud589\uc131 \uc218 n\uacfc \uc774\ubbf8 \uc124\uce58\ub41c \uad50\ud1b5 \ud154\ub808\ud3ec\ud130 \uc218 m\uc774 \uc8fc\uc5b4\uc9c4\ub2e4. (2 &le; n &le; 40,000, 0 &le; m &le; 1,000,000)<\/p>\r\n\r\n<p>\ub458\uc9f8 \uc904\ubd80\ud130 m\uac1c\uc758 \uc904\uc5d0 \uac78\uccd0 \uae30\uc874\uc758 \uac01 \ud154\ub808\ud3ec\ud130\uac00 \uc5f0\uacb0\ud55c \uc11c\ub85c \ub2e4\ub978 \ub450 \ud589\uc131\uc758 \ubc88\ud638\uac00 \uc8fc\uc5b4\uc9c4\ub2e4. \uac01 \ubc88\ud638\ub294 1 \uc774\uc0c1 n \uc774\ud558\uc758 \uc815\uc218\uc774\ub2e4. \uc5ec\uae30\uc5d4 \uc138\uc885\uc774\uc758 \uc804\uc6a9 \ud154\ub808\ud3ec\ud130\ub294 \ud3ec\ud568\ub418\uc5b4 \uc788\uc9c0 \uc54a\ub2e4. \uac19\uc740 \uacf3\uc744 \uc5f0\uacb0\ud558\ub294 \ud154\ub808\ud3ec\ud130\uac00 2\ubc88 \uc774\uc0c1 \ub4f1\uc7a5\ud558\uc9c0 \uc54a\ub294\ub2e4.<\/p>\r\n\r\n<p>\uae30\uc874\uc5d0 \uc5f0\uacb0\ub41c \ud154\ub808\ud3ec\ud130\ub9cc\uc744 \uac00\uc9c0\uace0\ub294 \uc5b4\ub5a0\ud55c \uacbd\ub85c\ub97c \uac70\uce58\ub354\ub77c\ub3c4 1\ubc88 \ud589\uc131\uacfc 2\ubc88 \ud589\uc131 \uc0ac\uc774\ub97c 250\ubd84 \ubbf8\ub9cc\uc758 \uc2dc\uac04\uc73c\ub85c \uc655\ub798\ud560 \uc218 \uc5c6\uc74c\uc774 \ubcf4\uc7a5\ub41c\ub2e4. \ubb3c\ub860 \uadf8 \uc774\uc0c1\uc774 \uc2dc\uac04\uc73c\ub85c \uc655\ub798\uac00 \uac00\ub2a5\ud560 \uc218\ub294 \uc788\ub2e4.<\/p>\r\n","output":"<p>\uccab\uc9f8 \uc904\uc5d0 \ucd94\uac00\ub85c \uac74\uc124\ud560 \uc218 \uc788\ub294 \ud154\ub808\ud3ec\ud130 \uac1c\uc218\uc758 \ucd5c\ub313\uac12\uc744 \ucd9c\ub825\ud55c\ub2e4.<\/p>\r\n","hint":"<p style=\"text-align: center;\"><img alt=\"\" src=\"https:\/\/onlinejudgeimages.s3-ap-northeast-1.amazonaws.com\/problem\/8193\/1.gif\" style=\"height:169px; width:157px\" \/><\/p>\r\n\r\n<p>\uc608\uc81c\ub97c \uadf8\ub9bc\uc73c\ub85c \ub098\ud0c0\ub0b8 \uac83\uc774\ub2e4. \uc2e4\uc120\uc774 \uc774\ubbf8 \uc5f0\uacb0\ub41c \ud154\ub808\ud3ec\ud130\uc774\uba70 \uc810\uc120\uc774 \ucd5c\ub300\ud55c \ub354 \uc9c0\uc744 \uc218 \uc788\ub294 \ud154\ub808\ud3ec\ud130\ub4e4\uc744 \ub098\ud0c0\ub0b8 \uac83\uc774\ub2e4.<\/p>\r\n","original":"0","html_title":"0","problem_lang_tcode":"Korean"},{"problem_id":"8193","problem_lang":"1","title":"Teleportation","description":"<p>King Byteasar is the ruler of the whole solar system that contains n planets. This number is so large that people have abandoned the silly custom of naming the planets and use numbers instead. The planets are thus conveniently numbered from 1 to n. Byteasar&#39;s palace is on the planet no. 1, while his military base on the planet no. 2. A long time ago Byteasar had a teleportation portal established between these two planets, which allows travelling from either planet to another in two hundred and fifty minutes (slightly over four hours).<\/p>\r\n\r\n<p>Nowadays the teleportation technology is more mature, and the recent teleportation devices shorten the travel time to just a single hour. Let us note here, that all the portals, both the Byteasar&#39;s old one and the new ones available on the market, are of course bidirectional, and that the teleportation travel time is irrespective of the distance travelled. Some planets of the system are already connected with these new teleportation portals. In fact, it is already possible to travel between the planets no. 1 and 2 without using the king&#39;s private portal, though this involves several other portals and is thus no faster than the king&#39;s portal. Byteasar finds this rather fortunate, as he believes that such possibility would be a security breach.<\/p>\r\n\r\n<p>The technology itself is increasingly available, and as everyone realises its economic significance, each pair of planets that are not currently directly connected with a portal are petitioning for establishing such a connection. Being a wise ruler, Byteasar intends to give his consent to as many constructions as possible, though keeping himself secure, i.e., not allowing the travel between planets 1 and 2 faster than with his private portal. Help the king determine how many portals he can agree to.<\/p>\r\n","input":"<p>Two integers are given in the first line of the standard input, n and m (2 &le; n &le; 40,000, 0 &le; m &le; 1,000,000), separated by a single space, denoting the number of planets in Byteasar&#39;s realm and the number of new portals that already exist. These teleportation portals are described in the m lines that follow. Each such line contains two integers a<sub>i<\/sub> and b<sub>i<\/sub> (1 &le; a<sub>i<\/sub> &lt; b<sub>i<\/sub> &le; n), separated by a single space, denoting that there is a teleportation portal of the new kind connecting ai and bi. No pair of numbers appears twice. You may assume that the existing network of new portals allows travel from planet no. 1 to planet no. 2, but in no less than 250 minutes.<\/p>\r\n\r\n<p>&nbsp;<\/p>\r\n","output":"<p>Your program should print out just a single integer, namely the maximum number of portals Byteasar can agree to without breaching his security.<\/p>\r\n\r\n<p>&nbsp;<\/p>\r\n","hint":"<p><img alt=\"\" src=\"https:\/\/onlinejudgeimages.s3-ap-northeast-1.amazonaws.com\/problem\/8193\/1.gif\" style=\"height:169px; width:157px\" \/><\/p>\r\n\r\n<p>Existing portals are marked with solid lines, while those Byteasar can agree to with dashed lines.<\/p>\r\n","original":"1","html_title":"0","problem_lang_tcode":"English"}]

출처

Olympiad > Polish Olympiad in Informatics > POI 2009/2010 > Stage 2 5번

  • 문제를 번역한 사람: kks227