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문제

월드피자 원주 지점에서 N개의 피자 반죽을 오븐에 넣고 구우려고 한다. 그런데, 월드피자에서 만드는 피자 반죽은 지름이 제각각이다. 그런가하면, 월드피자에서 사용하는 오븐의 모양도 몹시 오묘하다. 이 오븐은 깊은 관처럼 생겼는데, 관의 지름이 깊이에 따라 들쭉날쭉하게 변한다. 아래는 오븐의 단면 예시이다.

피자 반죽은 완성되는 순서대로 오븐에 들어간다. 이렇게 N개의 피자가 오븐에 모두 들어가고 나면, 맨 위의 피자가 얼마나 깊이 들어가 있는지가 궁금하다. 이를 알아내는 프로그램을 작성하시오.

입력

첫째 줄에 오븐의 깊이 D와 피자 반죽의 개수 N이 공백을 사이에 두고 주어진다. (1 ≤ D, N ≤ 300,000) 둘째 줄에는 오븐의 최상단부터 시작하여 깊이에 따른 오븐의 지름이 차례대로 주어진다. 셋째 줄에는 피자 반죽이 완성되는 순서대로, 그 각각의 지름이 주어진다. 오븐의 지름이나 피자 반죽의 지름은 10억 이하의 자연수이다.

출력

첫째 줄에, 마지막 피자 반죽의 위치를 출력한다. 오븐의 최상단이 1이고, 최하단 가장 깊은 곳이 D이 된다. 만약 피자가 모두 오븐에 들어가지 않는다면, 0을 출력한다.

예제 입력 1

7 3
5 6 4 3 6 2 3
3 2 5

예제 출력 1

2

힌트

[{"problem_id":"1756","problem_lang":"0","title":"\ud53c\uc790 \uad7d\uae30","description":"<p>\uc6d4\ub4dc\ud53c\uc790 \uc6d0\uc8fc \uc9c0\uc810\uc5d0\uc11c N\uac1c\uc758 \ud53c\uc790 \ubc18\uc8fd\uc744 \uc624\ube10\uc5d0 \ub123\uace0 \uad6c\uc6b0\ub824\uace0 \ud55c\ub2e4. \uadf8\ub7f0\ub370, \uc6d4\ub4dc\ud53c\uc790\uc5d0\uc11c \ub9cc\ub4dc\ub294 \ud53c\uc790 \ubc18\uc8fd\uc740 \uc9c0\ub984\uc774 \uc81c\uac01\uac01\uc774\ub2e4. \uadf8\ub7f0\uac00\ud558\uba74, \uc6d4\ub4dc\ud53c\uc790\uc5d0\uc11c \uc0ac\uc6a9\ud558\ub294 \uc624\ube10\uc758 \ubaa8\uc591\ub3c4 \ubab9\uc2dc \uc624\ubb18\ud558\ub2e4. \uc774 \uc624\ube10\uc740 \uae4a\uc740 \uad00\ucc98\ub7fc \uc0dd\uacbc\ub294\ub370, \uad00\uc758 \uc9c0\ub984\uc774 \uae4a\uc774\uc5d0 \ub530\ub77c \ub4e4\ucb49\ub0a0\ucb49\ud558\uac8c \ubcc0\ud55c\ub2e4. \uc544\ub798\ub294 \uc624\ube10\uc758 \ub2e8\uba74 \uc608\uc2dc\uc774\ub2e4.<\/p>\r\n\r\n<p style=\"text-align: center;\"><img alt=\"\" src=\"https:\/\/onlinejudgeimages.s3-ap-northeast-1.amazonaws.com\/upload\/201006\/pizz1.PNG\" style=\"height:157px; width:268px\" \/><\/p>\r\n\r\n<p>\ud53c\uc790 \ubc18\uc8fd\uc740 \uc644\uc131\ub418\ub294 \uc21c\uc11c\ub300\ub85c \uc624\ube10\uc5d0 \ub4e4\uc5b4\uac04\ub2e4. \uc774\ub807\uac8c N\uac1c\uc758 \ud53c\uc790\uac00 \uc624\ube10\uc5d0 \ubaa8\ub450 \ub4e4\uc5b4\uac00\uace0 \ub098\uba74, \ub9e8 \uc704\uc758 \ud53c\uc790\uac00 \uc5bc\ub9c8\ub098 \uae4a\uc774 \ub4e4\uc5b4\uac00 \uc788\ub294\uc9c0\uac00 \uad81\uae08\ud558\ub2e4. \uc774\ub97c \uc54c\uc544\ub0b4\ub294 \ud504\ub85c\uadf8\ub7a8\uc744 \uc791\uc131\ud558\uc2dc\uc624.<\/p>\r\n","input":"<p>\uccab\uc9f8 \uc904\uc5d0 \uc624\ube10\uc758 \uae4a\uc774 D\uc640 \ud53c\uc790 \ubc18\uc8fd\uc758 \uac1c\uc218 N\uc774 \uacf5\ubc31\uc744 \uc0ac\uc774\uc5d0 \ub450\uace0 \uc8fc\uc5b4\uc9c4\ub2e4. (1 &le; D, N &le; 300,000) \ub458\uc9f8 \uc904\uc5d0\ub294 \uc624\ube10\uc758 \ucd5c\uc0c1\ub2e8\ubd80\ud130 \uc2dc\uc791\ud558\uc5ec \uae4a\uc774\uc5d0 \ub530\ub978 \uc624\ube10\uc758 \uc9c0\ub984\uc774 \ucc28\ub840\ub300\ub85c \uc8fc\uc5b4\uc9c4\ub2e4. \uc14b\uc9f8 \uc904\uc5d0\ub294 \ud53c\uc790 \ubc18\uc8fd\uc774 \uc644\uc131\ub418\ub294 \uc21c\uc11c\ub300\ub85c, \uadf8 \uac01\uac01\uc758 \uc9c0\ub984\uc774 \uc8fc\uc5b4\uc9c4\ub2e4. \uc624\ube10\uc758 \uc9c0\ub984\uc774\ub098 \ud53c\uc790 \ubc18\uc8fd\uc758 \uc9c0\ub984\uc740 10\uc5b5 \uc774\ud558\uc758 \uc790\uc5f0\uc218\uc774\ub2e4.<\/p>\r\n","output":"<p>\uccab\uc9f8 \uc904\uc5d0, \ub9c8\uc9c0\ub9c9 \ud53c\uc790 \ubc18\uc8fd\uc758&nbsp;\uc704\uce58\ub97c \ucd9c\ub825\ud55c\ub2e4. \uc624\ube10\uc758 \ucd5c\uc0c1\ub2e8\uc774 1\uc774\uace0, \ucd5c\ud558\ub2e8 \uac00\uc7a5 \uae4a\uc740 \uacf3\uc774 D\uc774 \ub41c\ub2e4. \ub9cc\uc57d \ud53c\uc790\uac00 \ubaa8\ub450 \uc624\ube10\uc5d0 \ub4e4\uc5b4\uac00\uc9c0 \uc54a\ub294\ub2e4\uba74, 0\uc744 \ucd9c\ub825\ud55c\ub2e4.<\/p>\r\n","hint":"<p><img alt=\"\" src=\"\/JudgeOnline\/upload\/201006\/piz2.PNG\" style=\"height:156px; width:266px\" \/><\/p>\r\n","original":"0","html_title":"0","problem_lang_tcode":"Korean"},{"problem_id":"1756","problem_lang":"1","title":"The Disks","description":"<p>For his birthday present little Johnny has received from his parents a new plaything which consists of a tube and a set of disks. The aforementioned tube is of unusual shape. Namely, it is made of a certain number of cylinders (of equal height) with apertures of different diameters carved coaxially through them. The tube is closed at the bottom, open at the top. An exemplary tube consisting of cylinders whose apertures have the diameters: 5cm, 6cm, 4cm, 3cm, 6cm, 2cm and 3cm is presented in the image below.<\/p>\r\n\r\n<p><img alt=\"\" src=\"\/upload\/images\/kra1.png\" style=\"height:206px; width:350px\" \/><\/p>\r\n\r\n<p>The disks in Johnny&#39;s plaything are cylinders of different diameters and height equal to those forming the tube.<\/p>\r\n\r\n<p>Johnny has invented a following game: having a certain set of disks at his disposal, he seeks to find what depth the last of them would stop at, assuming that they are being thrown into the centre of the tube. If, for instance, we were to throw disks of consecutive diameters: 3cm, 2cm and 5cm, we would obtain the following situation:<\/p>\r\n\r\n<p><img alt=\"\" src=\"\/upload\/images\/kra2.png\" style=\"height:206px; width:350px\" \/><\/p>\r\n\r\n<p>As you can see, upon being thrown in, every disk falls until it gets stuck (which means that it lies atop a cylinder, aperture of which has a diameter smaller than the diameter of the disk) or it is stopped by an obstacle: the bottom of the tube or another disk, which has already stopped.<\/p>\r\n\r\n<p>The game being difficult, Johnny constantly asks his parents for help. As Johnny&#39;s parents do not like such intellectual games, they have asked you - an acquaintance of theirs and a programmer - to write a programme which will provide them with answers to Johnny&#39;s questions.<\/p>\r\n\r\n<p>Write a programme which:<\/p>\r\n\r\n<ul>\r\n\t<li>reads the description of the tube and the disks which Johnny will throw into it from the standard input,<\/li>\r\n\t<li>computes the depth which the last disk thrown by Johnny stops at,<\/li>\r\n\t<li>writes the outcome to the standard output.<\/li>\r\n<\/ul>\r\n","input":"<p>The first line of the standard input contains two integers n and m (1 &le; n,m &le; 300 000) separated by a single space and denoting the height of Johnny&#39;s tube (the number of cylinders it comprises) and the number of disks Johnny intends to throw into it, respectively. The second line of the standard input contains n integers r<sub>1<\/sub>,r<sub>2<\/sub>,...,r<sub>n<\/sub> (1 &le; r<sub>i<\/sub> &le; 1 000 000 000 for 1 &le; i &le; n) separated by single spaces and denoting the diameters of the apertures carved through the consecutive cylinders (in top-down order), which the tube consists of. The third line contains m integers k<sub>1<\/sub>,k<sub>2<\/sub>,...,k<sub>m<\/sub> (1 &le; k<sub>j<\/sub> &le; 1 000 000 000 for 1 &le; j &le; m) separated by single spaces and denoting the diameters of consecutive disks which Johnny intends to throw into the tube.<\/p>\r\n\r\n<p>&nbsp;<\/p>\r\n","output":"<p>The first and only line of the standard output should contain a single integer denoting the depth which the last disk stops at. Should the disk not fall into the tube at all, the answer should be 0.<\/p>\r\n\r\n<p>&nbsp;<\/p>\r\n","hint":"","original":"1","html_title":"0","problem_lang_tcode":"English"}]

출처

Olympiad > Polish Olympiad in Informatics > POI 2005/2006 > Stage 1 1번