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#F0999. Vladik and cards

    ID: 1005 传统题 2000ms 256MiB 尝试: 0 已通过: 0 难度: 7 上传者: 标签>二分位运算枚举动态规划算法思想数学提高难度共享题库Codeforces英文题面题目来源题面语言

Vladik and cards

题目描述

E. Vladik and cards
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

Vladik was bored on his way home and decided to play the following game. He took n cards and put them in a row in front of himself. Every card has a positive integer number not exceeding 8 written on it. He decided to find the longest subsequence of cards which satisfies the following conditions:

  • the number of occurrences of each number from 1 to 8 in the subsequence doesn't differ by more then 1 from the number of occurrences of any other number. Formally, if there are ck cards with number k on them in the subsequence, than for all pairs of integers the condition |ci-cj|≤1 must hold.
  • if there is at least one card with number x on it in the subsequence, then all cards with number x in this subsequence must form a continuous segment in it (but not necessarily a continuous segment in the original sequence). For example, the subsequence [1,1,2,2] satisfies this condition while the subsequence [1,2,2,1] doesn't. Note that [1,1,2,2] doesn't satisfy the first condition.

Please help Vladik to find the length of the longest subsequence that satisfies both conditions.

Input

The first line contains single integer n (1≤n≤1000)− the number of cards in Vladik's sequence.

The second line contains the sequence of n positive integers not exceeding 8− the description of Vladik's sequence.

Output

Print single integer− the length of the longest subsequence of Vladik's sequence that satisfies both conditions.

Examples
Input
3
1 1 1
Output
1
Input
8
8 7 6 5 4 3 2 1
Output
8
Input
24
1 8 1 2 8 2 3 8 3 4 8 4 5 8 5 6 8 6 7 8 7 8 8 8
Output
17
Note

In the first sample all the numbers written on the cards are equal, so you can't take more than one card, otherwise you'll violate the first condition.


题目来源:fps-www.educg.net-codeforce-1-2833.xml.zip;FPS 共享题包,题包内第 446 题。保留原作者与原赛事署名。