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문제

상근이의 상상의 친구 외계인은 손가락을 수십억개 가지고 있다. 어느 날 외계인은 기타가 치고 싶었고, 인터넷에서 간단한 멜로디를 검색했다. 이제 이 기타를 치려고 한다.

보통 기타는 1번 줄부터 6번 줄까지 총 6개의 줄이 있고, 각 줄은 P개의 프렛으로 나누어져 있다. 프렛의 번호도 1번부터 P번까지 나누어져 있다.

멜로디는 음의 연속이고, 각 음은 줄에서 해당하는 프렛을 누르고 줄을 튕기면 연주할 수 있다. 예를 들면, 4번 줄의 8번 프렛을 누르고 튕길 수 있다. 만약, 어떤 줄의 프렛을 여러 개 누르고 있다면, 가장 높은 프렛의 음이 발생한다.

예를 들어, 3번 줄의 5번 프렛을 이미 누르고 있다고 하자. 이때, 7번 프렛을 누른 음을 연주하려면, 5번 프렛을 누르는 손을 떼지 않고 다른 손가락으로 7번 프렛을 누르고 줄을 튕기면 된다. 여기서 2번 프렛의 음을 연주하려고 한다면, 5번과 7번을 누르던 손가락을 뗀 다음에 2번 프렛을 누르고 연주해야 한다.

이렇게 손가락으로 프렛을 한 번 누르거나 떼는 것을 손가락을 한 번 움직였다고 한다. 어떤 멜로디가 주어졌을 때, 손가락의 가장 적게 움직이는 회수를 구하는 프로그램을 작성하시오.

입력

첫째 줄에 멜로디에 포함되어 있는 음의 수 N과 한 줄에 있는 프렛의 수 P가 주어진다. (1 ≤ N ≤ 500,000, 2 ≤ P ≤ 300,000)

다음 N개 줄에는 멜로디의 한 음을 나타내는 두 정수가 주어진다. 첫 번째 정수는 줄의 번호이고 두 번째 정수는 그 줄에서 눌러야 하는 프렛의 번호이다. 입력으로 주어진 음의 순서대로 기타를 연주해야 한다. 줄의 번호는 N보다 작거나 같은 자연수이고, 프렛의 번호도 P보다 작거나 같은 자연수이다.

출력

첫째 줄에 멜로디를 연주하는데 필요한 최소 손가락 움직임을 출력한다.

예제 입력 1

5 15
2 8
2 10
2 12
2 10
2 5

예제 출력 1

7

예제 입력 2

7 15
1 5
2 3
2 5
2 7
2 4
1 5
1 3

예제 출력 2

9
[{"problem_id":"2841","problem_lang":"0","title":"\uc678\uacc4\uc778\uc758 \uae30\ud0c0 \uc5f0\uc8fc","description":"<p>\uc0c1\uadfc\uc774\uc758 \uc0c1\uc0c1\uc758 \uce5c\uad6c \uc678\uacc4\uc778\uc740 \uc190\uac00\ub77d\uc744 \uc218\uc2ed\uc5b5\uac1c \uac00\uc9c0\uace0 \uc788\ub2e4. \uc5b4\ub290 \ub0a0 \uc678\uacc4\uc778\uc740 \uae30\ud0c0\uac00 \uce58\uace0 \uc2f6\uc5c8\uace0, \uc778\ud130\ub137\uc5d0\uc11c \uac04\ub2e8\ud55c \uba5c\ub85c\ub514\ub97c \uac80\uc0c9\ud588\ub2e4. \uc774\uc81c \uc774 \uae30\ud0c0\ub97c \uce58\ub824\uace0 \ud55c\ub2e4.<\/p>\r\n\r\n<p>\ubcf4\ud1b5 \uae30\ud0c0\ub294 1\ubc88 \uc904\ubd80\ud130 6\ubc88 \uc904\uae4c\uc9c0 \ucd1d 6\uac1c\uc758 \uc904\uc774 \uc788\uace0, \uac01 \uc904\uc740 P\uac1c\uc758 \ud504\ub81b\uc73c\ub85c \ub098\ub204\uc5b4\uc838 \uc788\ub2e4. \ud504\ub81b\uc758 \ubc88\ud638\ub3c4 1\ubc88\ubd80\ud130 P\ubc88\uae4c\uc9c0 \ub098\ub204\uc5b4\uc838 \uc788\ub2e4.<\/p>\r\n\r\n<p>\uba5c\ub85c\ub514\ub294 \uc74c\uc758 \uc5f0\uc18d\uc774\uace0, \uac01 \uc74c\uc740 \uc904\uc5d0\uc11c \ud574\ub2f9\ud558\ub294 \ud504\ub81b\uc744 \ub204\ub974\uace0 \uc904\uc744 \ud295\uae30\uba74 \uc5f0\uc8fc\ud560 \uc218 \uc788\ub2e4. \uc608\ub97c \ub4e4\uba74, 4\ubc88 \uc904\uc758 8\ubc88 \ud504\ub81b\uc744 \ub204\ub974\uace0 \ud295\uae38 \uc218 \uc788\ub2e4. \ub9cc\uc57d, \uc5b4\ub5a4 \uc904\uc758 \ud504\ub81b\uc744 \uc5ec\ub7ec \uac1c \ub204\ub974\uace0 \uc788\ub2e4\uba74, \uac00\uc7a5 \ub192\uc740 \ud504\ub81b\uc758 \uc74c\uc774 \ubc1c\uc0dd\ud55c\ub2e4.<\/p>\r\n\r\n<p>\uc608\ub97c \ub4e4\uc5b4, 3\ubc88 \uc904\uc758 5\ubc88 \ud504\ub81b\uc744 \uc774\ubbf8 \ub204\ub974\uace0 \uc788\ub2e4\uace0 \ud558\uc790. \uc774\ub54c, 7\ubc88 \ud504\ub81b\uc744 \ub204\ub978 \uc74c\uc744 \uc5f0\uc8fc\ud558\ub824\uba74, 5\ubc88 \ud504\ub81b\uc744 \ub204\ub974\ub294 \uc190\uc744 \ub5bc\uc9c0 \uc54a\uace0 \ub2e4\ub978 \uc190\uac00\ub77d\uc73c\ub85c 7\ubc88 \ud504\ub81b\uc744 \ub204\ub974\uace0 \uc904\uc744 \ud295\uae30\uba74 \ub41c\ub2e4. \uc5ec\uae30\uc11c 2\ubc88 \ud504\ub81b\uc758 \uc74c\uc744 \uc5f0\uc8fc\ud558\ub824\uace0 \ud55c\ub2e4\uba74, 5\ubc88\uacfc 7\ubc88\uc744 \ub204\ub974\ub358 \uc190\uac00\ub77d\uc744 \ub5c0 \ub2e4\uc74c\uc5d0 2\ubc88 \ud504\ub81b\uc744 \ub204\ub974\uace0 \uc5f0\uc8fc\ud574\uc57c \ud55c\ub2e4.<\/p>\r\n\r\n<p>\uc774\ub807\uac8c \uc190\uac00\ub77d\uc73c\ub85c \ud504\ub81b\uc744 \ud55c \ubc88 \ub204\ub974\uac70\ub098 \ub5bc\ub294 \uac83\uc744 \uc190\uac00\ub77d\uc744 \ud55c \ubc88 \uc6c0\uc9c1\uc600\ub2e4\uace0 \ud55c\ub2e4. \uc5b4\ub5a4 \uba5c\ub85c\ub514\uac00 \uc8fc\uc5b4\uc84c\uc744 \ub54c, \uc190\uac00\ub77d\uc758 \uac00\uc7a5 \uc801\uac8c \uc6c0\uc9c1\uc774\ub294 \ud68c\uc218\ub97c \uad6c\ud558\ub294 \ud504\ub85c\uadf8\ub7a8\uc744 \uc791\uc131\ud558\uc2dc\uc624.<\/p>\r\n","input":"<p>\uccab\uc9f8 \uc904\uc5d0 \uba5c\ub85c\ub514\uc5d0 \ud3ec\ud568\ub418\uc5b4 \uc788\ub294 \uc74c\uc758 \uc218 N\uacfc \ud55c \uc904\uc5d0 \uc788\ub294 \ud504\ub81b\uc758 \uc218 P\uac00 \uc8fc\uc5b4\uc9c4\ub2e4. (1 &le; N &le; 500,000, 2 &le; P &le; 300,000)<\/p>\r\n\r\n<p>\ub2e4\uc74c N\uac1c \uc904\uc5d0\ub294 \uba5c\ub85c\ub514\uc758 \ud55c \uc74c\uc744 \ub098\ud0c0\ub0b4\ub294 \ub450 \uc815\uc218\uac00 \uc8fc\uc5b4\uc9c4\ub2e4. \uccab \ubc88\uc9f8 \uc815\uc218\ub294 \uc904\uc758 \ubc88\ud638\uc774\uace0 \ub450 \ubc88\uc9f8 \uc815\uc218\ub294 \uadf8 \uc904\uc5d0\uc11c \ub20c\ub7ec\uc57c \ud558\ub294 \ud504\ub81b\uc758 \ubc88\ud638\uc774\ub2e4. \uc785\ub825\uc73c\ub85c \uc8fc\uc5b4\uc9c4 \uc74c\uc758 \uc21c\uc11c\ub300\ub85c \uae30\ud0c0\ub97c \uc5f0\uc8fc\ud574\uc57c \ud55c\ub2e4. \uc904\uc758 \ubc88\ud638\ub294 N\ubcf4\ub2e4 \uc791\uac70\ub098 \uac19\uc740 \uc790\uc5f0\uc218\uc774\uace0, \ud504\ub81b\uc758 \ubc88\ud638\ub3c4 P\ubcf4\ub2e4 \uc791\uac70\ub098 \uac19\uc740 \uc790\uc5f0\uc218\uc774\ub2e4.<\/p>\r\n","output":"<p>\uccab\uc9f8 \uc904\uc5d0 \uba5c\ub85c\ub514\ub97c \uc5f0\uc8fc\ud558\ub294\ub370 \ud544\uc694\ud55c \ucd5c\uc18c \uc190\uac00\ub77d \uc6c0\uc9c1\uc784\uc744 \ucd9c\ub825\ud55c\ub2e4.<\/p>\r\n","hint":"","original":"0","html_title":"0","problem_lang_tcode":"Korean"},{"problem_id":"2841","problem_lang":"1","title":"GITARA","description":"<p>Darko has a new imaginary extraterrestrial friend with a billion of fingers. The extraterrestrial has soon took hold of his guitar, found a simple melody online, and started playing it.<\/p>\r\n\r\n<p>The guitar, as usual, has six strings denoted by numbers 1 through 6. Each string is divided into P frets denoted by numbers 1 through P.<\/p>\r\n\r\n<p>A melody is a sequence of tones, where each tone is produced by picking a string pressed on a specific fret (e.g. 4th string pressed on the 8th fret). If a string is pressed on several frets, the produced tone will be the one corresponding to the highest of those frets.<\/p>\r\n\r\n<p>For instance, if the 3rd string is already pressed on the 5th fret, and the tone which corresponds to the 7th fret is to be produced, the string can be pressed on the 7th fret and picked without releasing the 5th fret, since only the highest one affects the tone produced (7th in this case). Similarly, if a tone that corresponds to the 2nd fret on the same string is next to be produced, it is necessary to release both 5th and 7th frets.<\/p>\r\n\r\n<p>Write a program which computes the minimum number of finger movements needed to produce the given melody. Note that press or release a single fret counts as one finger move. String picking does not count as finger move, but rather a guitar pick move.<\/p>\r\n","input":"<p>The first line of input contains two positive integers separated by a single space, N (N &le; 500 000) and P (2 &le; P &le; 300 000). They represent the number of tones in the melody and the number of frets, respectively.<\/p>\r\n\r\n<p>The following N lines describe the fields for the corresponding tones &ndash; the ordinal of the string and the ordinal of the fret, respectively, in the same order as the extraterrestrial play them.<\/p>\r\n","output":"<p>In a single line of output, print the minimum number of finger movements.<\/p>\r\n","hint":"<p>First sample description: all the tones played are produced by picking the 2nd string. First, the frets 8, 10, 12 are pressed, in order (three movements). Then, the 12th fret is released to produce the second tone again (fourth movement). Finally, the 5th fret is pressed followed by the release of frets 10 and 12 (a total of seven movements).<\/p>\r\n\r\n<p>Second sample description: 1, 1, 1, 1, 3, 0, 2 finger movements are necessary, in the order of the seven tones produced.<\/p>\r\n","original":"1","html_title":"0","problem_lang_tcode":"English"}]

출처

Contest > Croatian Open Competition in Informatics > COCI 2010/2011 > Contest #7 3번

  • 문제를 번역한 사람: baekjoon
  • 문제의 오타를 찾은 사람: wxogus25