시간 제한메모리 제한제출정답맞힌 사람정답 비율
1 초 128 MB38615512740.836%

문제

JOIOI 탑은 원반을 이용해서 혼자 재미있게 놀 수 있는 게임이다.

이 게임은 J, O, I중 하나의 문자가 쓰여진 원반을 이용한다. 원반은 모두 반지름이 다르다. 가장 처음에 원반은 반지름이 큰 것이 가장 아래에 있고, 나머지는 작아지는 순서대로 쌓여 있다.

상근이는 이 원반을 이용해 가능한 많은 미니 JOIOI 탑을 만들려고 한다. 미니 JOIOI 탑은 3개의 원반으로 구성되며, 반지름이 작은 것부터 읽었을 때 JOIIOI이어야 한다. 한 미니 JOIOI 탑에 속한 원반은 다른 탑에 속할 수 없다.

반지름이 작은 원반부터 순서대로 원반에 적혀져 있는 문자가 순서대로 주어진다. 이때, 만들 수 있는 미니 JOIOI 탑의 최대 개수를 구하는 프로그램을 작성하시오.

입력

첫째 줄에 원반의 개수 N이 주어진다. 둘째 줄에는 원반에 적혀있는 문자가 반지름이 작은 순서대로 주어진다. (1 ≤ N ≤ 1,000,000)

출력

첫째 줄에 만들 수 있는 미니 JOIOI 탑의 최대 개수를 출력한다.

예제 입력 1

6
JOIIOI

예제 출력 1

2

예제 입력 2

5
JOIOI

예제 출력 2

1

예제 입력 3

6
JOIOII

예제 출력 3

2

예제 입력 4

15
JJOIIOOJOJIOIIO

예제 출력 4

4
[{"problem_id":"5530","problem_lang":"0","title":"JOIOI \ud0d1","description":"<p>JOIOI \ud0d1\uc740 \uc6d0\ubc18\uc744 \uc774\uc6a9\ud574\uc11c \ud63c\uc790 \uc7ac\ubbf8\uc788\uac8c \ub180 \uc218 \uc788\ub294 \uac8c\uc784\uc774\ub2e4.<\/p>\r\n\r\n<p>\uc774 \uac8c\uc784\uc740 <code>J<\/code>, <code>O<\/code>, <code>I<\/code>\uc911 \ud558\ub098\uc758 \ubb38\uc790\uac00 \uc4f0\uc5ec\uc9c4 \uc6d0\ubc18\uc744 \uc774\uc6a9\ud55c\ub2e4. \uc6d0\ubc18\uc740 \ubaa8\ub450 \ubc18\uc9c0\ub984\uc774 \ub2e4\ub974\ub2e4. \uac00\uc7a5 \ucc98\uc74c\uc5d0 \uc6d0\ubc18\uc740 \ubc18\uc9c0\ub984\uc774 \ud070 \uac83\uc774 \uac00\uc7a5 \uc544\ub798\uc5d0 \uc788\uace0, \ub098\uba38\uc9c0\ub294 \uc791\uc544\uc9c0\ub294 \uc21c\uc11c\ub300\ub85c \uc313\uc5ec \uc788\ub2e4.<\/p>\r\n\r\n<p>\uc0c1\uadfc\uc774\ub294 \uc774 \uc6d0\ubc18\uc744 \uc774\uc6a9\ud574 \uac00\ub2a5\ud55c \ub9ce\uc740 \ubbf8\ub2c8 JOIOI \ud0d1\uc744 \ub9cc\ub4e4\ub824\uace0 \ud55c\ub2e4. \ubbf8\ub2c8 JOIOI \ud0d1\uc740 3\uac1c\uc758 \uc6d0\ubc18\uc73c\ub85c \uad6c\uc131\ub418\uba70, \ubc18\uc9c0\ub984\uc774 \uc791\uc740 \uac83\ubd80\ud130 \uc77d\uc5c8\uc744 \ub54c <code>JOI<\/code>\ub098 <code>IOI<\/code>\uc774\uc5b4\uc57c \ud55c\ub2e4. \ud55c \ubbf8\ub2c8 JOIOI \ud0d1\uc5d0 \uc18d\ud55c \uc6d0\ubc18\uc740 \ub2e4\ub978 \ud0d1\uc5d0 \uc18d\ud560 \uc218 \uc5c6\ub2e4.<\/p>\r\n\r\n<p style=\"text-align: center;\"><img alt=\"\" src=\"https:\/\/upload.acmicpc.net\/58cba022-9053-4e69-964f-425f944d359b\/-\/preview\/\" style=\"width: 332px; height: 199px;\" \/><\/p>\r\n\r\n<p>\ubc18\uc9c0\ub984\uc774 \uc791\uc740 \uc6d0\ubc18\ubd80\ud130 \uc21c\uc11c\ub300\ub85c \uc6d0\ubc18\uc5d0 \uc801\ud600\uc838 \uc788\ub294 \ubb38\uc790\uac00 \uc21c\uc11c\ub300\ub85c \uc8fc\uc5b4\uc9c4\ub2e4. \uc774\ub54c, \ub9cc\ub4e4 \uc218 \uc788\ub294 \ubbf8\ub2c8 JOIOI \ud0d1\uc758 \ucd5c\ub300 \uac1c\uc218\ub97c \uad6c\ud558\ub294 \ud504\ub85c\uadf8\ub7a8\uc744 \uc791\uc131\ud558\uc2dc\uc624.<\/p>\r\n","input":"<p>\uccab\uc9f8 \uc904\uc5d0 \uc6d0\ubc18\uc758 \uac1c\uc218 N\uc774 \uc8fc\uc5b4\uc9c4\ub2e4. \ub458\uc9f8 \uc904\uc5d0\ub294 \uc6d0\ubc18\uc5d0 \uc801\ud600\uc788\ub294 \ubb38\uc790\uac00 \ubc18\uc9c0\ub984\uc774 \uc791\uc740 \uc21c\uc11c\ub300\ub85c \uc8fc\uc5b4\uc9c4\ub2e4. (1 &le; N &le; 1,000,000)<\/p>\r\n","output":"<p>\uccab\uc9f8 \uc904\uc5d0 \ub9cc\ub4e4 \uc218 \uc788\ub294 \ubbf8\ub2c8 JOIOI \ud0d1\uc758 \ucd5c\ub300 \uac1c\uc218\ub97c \ucd9c\ub825\ud55c\ub2e4.<\/p>\r\n","hint":"","original":"0","html_title":"0","problem_lang_tcode":"Korean"},{"problem_id":"5530","problem_lang":"2","title":"JOIOI \u306e\u5854 (Tower of JOIOI)","description":"<p>JOIOI \u306e\u5854\u3068\u306f\uff0c1 \u4eba\u3067\u904a\u3076\u5186\u76e4\u3092\u4f7f\u3063\u305f\u30b2\u30fc\u30e0\u3067\u3042\u308b\uff0e<\/p>\r\n\r\n<p>\u3053\u306e\u30b2\u30fc\u30e0\u306f\uff0c<code>J<\/code>\uff0c<code>O<\/code>\uff0c<code>I<\/code> \u306e\u3044\u305a\u308c\u304b\u306e\u6587\u5b57\u304c\u66f8\u304b\u308c\u305f\u3044\u304f\u3064\u304b\u306e\u5186\u76e4\u3092\u7528\u3044\u3066\u884c\u3046\uff0e\u5186\u76e4\u306f\u76f4\u5f84\u304c\u4e92\u3044\u306b\u7570\u306a\u308a\uff0c\u30b2\u30fc\u30e0\u958b\u59cb\u6642\u306b\u306f\u3053\u308c\u3089\u306e\u5186\u76e4\u306f\u76f4\u5f84\u306e\u5927\u304d\u3044\u3082\u306e\u304b\u3089\u9806\u306b\u4e0b\u304b\u3089\u4e0a\u306b\u5411\u304b\u3063\u3066\u7a4d\u307e\u308c\u3066\u3044\u308b\uff0e\u3042\u306a\u305f\u306f\uff0c\u3053\u308c\u3089\u306e\u5186\u76e4\u3092\u7528\u3044\u3066\uff0c\u51fa\u6765\u308b\u3060\u3051\u591a\u304f\u306e\u30df\u30cb JOIOI \u306e\u5854\u3092\u4f5c\u308a\u305f\u3044\uff0e\u30df\u30cb JOIOI \u306e\u5854\u3068\u306f 3\u679a\u306e\u5186\u76e4\u304b\u3089\u306a\u308a\uff0c\u5186\u76e4\u306e\u76f4\u5f84\u304c\u5c0f\u3055\u3044\u3082\u306e\u304b\u3089\u9806\u306b\u8aad\u3093\u3067 <code>JOI<\/code> \u3082\u3057\u304f\u306f <code>IOI<\/code> \u3068\u8aad\u3081\u308b\u3082\u306e\u3067\u3042\u308b\uff0e\u305f\u3060\u3057\uff0c\u540c\u3058\u5186\u76e4\u3092 2 \u5ea6\u4ee5\u4e0a\u4f7f\u3046\u3053\u3068\u306f\u3067\u304d\u306a\u3044\uff0e<\/p>\r\n\r\n<p style=\"text-align: center;\"><img alt=\"\" src=\"https:\/\/upload.acmicpc.net\/58cba022-9053-4e69-964f-425f944d359b\/-\/preview\/\" style=\"width: 332px; height: 199px;\" \/><\/p>\r\n\r\n<p style=\"text-align: center;\">\u56f3: <code>JOIOII<\/code> \u304b\u3089\u306f\u30df\u30cb JOIOI \u306e\u5854\u304c 2 \u3064\u4f5c\u308c\u308b<\/p>\r\n\r\n<p>\u7528\u610f\u3055\u308c\u305f\u5186\u76e4\u306b\u66f8\u304b\u308c\u305f\u6587\u5b57\u304c\u305d\u308c\u305e\u308c\u5186\u76e4\u306e\u76f4\u5f84\u304c\u5c0f\u3055\u3044\u3082\u306e\u304b\u3089\u9806\u306b\u9577\u3055 N \u306e\u6587\u5b57\u5217 S \u3068\u3057\u3066\u4e0e\u3048\u3089\u308c\u308b\uff0e\u3053\u308c\u3089\u306e\u5186\u76e4\u3092\u4f7f\u3063\u3066\u4f5c\u308b\u3053\u3068\u306e\u3067\u304d\u308b\u30df\u30cb JOIOI \u306e\u5854\u306e\u500b\u6570\u306e\u6700\u5927\u5024\u3092\u6c42\u3081\u308b\u30d7\u30ed\u30b0\u30e9\u30e0\u3092\u4f5c\u6210\u305b\u3088\uff0e<\/p>\r\n","input":"<p>\u6a19\u6e96\u5165\u529b\u304b\u3089\u4ee5\u4e0b\u306e\u30c7\u30fc\u30bf\u3092\u8aad\u307f\u8fbc\u3081\uff0e<\/p>\r\n\r\n<ul>\r\n\t<li>1 \u884c\u76ee\u306b\u306f\u6574\u6570 N \u304c\u66f8\u304b\u308c\u3066\u3044\u308b\uff0eN \u306f\u6587\u5b57\u5217 S \u306e\u9577\u3055\u3092\u8868\u3059\uff0e<\/li>\r\n\t<li>2 \u884c\u76ee\u306b\u306f\u6587\u5b57\u5217 S \u304c\u66f8\u304b\u308c\u3066\u3044\u308b\uff0e<\/li>\r\n<\/ul>\r\n","output":"<p>\u6a19\u6e96\u51fa\u529b\u306b\uff0c\u4f5c\u308b\u3053\u3068\u306e\u3067\u304d\u308b\u30df\u30cb JOIOI \u306e\u5854\u306e\u6570\u306e\u6700\u5927\u5024\u3092\u8868\u3059\u6574\u6570\u3092 1 \u884c\u3067\u51fa\u529b\u305b\u3088\uff0e<\/p>\r\n","hint":"","original":"1","html_title":"0","problem_lang_tcode":"Japanese","limit":"<p>1 &le; N &le; 1 000 000 \u6587\u5b57\u5217 S \u306e\u9577\u3055<\/p>\r\n","sample_explain_1":"<p><code>JOIIOI<\/code> \u306f <code>JOI<\/code> \u304a\u3088\u3073 <code>IOI<\/code> \u3092\u305d\u308c\u305e\u308c 1 \u3064\u305a\u3064\u90e8\u5206\u5217\u3068\u3057\u3066\u542b\u3093\u3067\u304a\u308a\uff0c\u4f5c\u308b\u3053\u3068\u306e\u3067\u304d\u308b\u30df\u30cb JOIOI \u306e\u5854\u306f 2 \u3064\u3067\u3042\u308b\uff0e<\/p>\r\n","sample_explain_2":"<p>\u90e8\u5206\u5217\u3068\u3057\u3066 <code>JOI<\/code> \u304a\u3088\u3073 <code>IOI<\/code> \u3092\u542b\u3093\u3067\u3044\u308b\u304c\uff0c\u6587\u5b57\u3092 2 \u5ea6\u4ee5\u4e0a\u4f7f\u3046\u3053\u3068\u306f\u3067\u304d\u306a\u3044\u305f\u3081\u540c\u6642\u306b\u53d6\u308a\u51fa\u3059 \u3053\u3068\u306f\u3067\u304d\u306a\u3044\uff0e<\/p>\r\n","sample_explain_3":"<p>\u3053\u306e\u5165\u51fa\u529b\u4f8b\u306f\u554f\u984c\u6587\u4e2d\u306e\u4f8b\u306b\u5bfe\u5fdc\u3057\u3066\u3044\u308b\uff0e<\/p>\r\n"}]

출처

Olympiad > Japanese Olympiad in Informatics > JOI 2013 4번