题目描述

Bessie likes downloading games to play on her cell phone, even though she doesfind the small touch screen rather cumbersome to use with her large hooves.

She is particularly intrigued by the current game she is playing.The game starts with a sequence of $N$ positive integers ($2 \leq N\leq 248$), each in the range $1 \ldots 40$. In one move, Bessie cantake two adjacent numbers with equal values and replace them a singlenumber of value one greater (e.g., she might replace two adjacent 7s with an 8). The goal is to maximize the value of the largest numberpresent in the sequence at the end of the game. Please help Bessiescore as highly as possible!

输入格式

The first line of input contains $N$, and the next $N$ lines give the sequence of $N$ numbers at the start of the game.

输出格式

Please output the largest integer Bessie can generate.

题目大意

题目描述

贝西喜欢在手机上下载游戏来玩，尽管她确实觉得对于自己巨大的蹄子来说，小小的触摸屏用起来相当笨拙。

她对当前正在玩的这个游戏特别感兴趣。游戏开始时给定一个包含 $N$ 个正整数的序列（$2 \leq N \leq 248$），每个数的范围在 $1 \ldots 40$ 之间。在一次操作中，贝西可以选择两个相邻且相等的数，将它们替换为一个比原数大 1 的数（例如，她可以将两个相邻的 7 替换为一个 8）。游戏的目标是最大化最终序列中的最大数值。请帮助贝西获得尽可能高的分数！

输入格式

第一行输入包含 $N$，接下来的 $N$ 行给出游戏开始时序列的 $N$ 个数字。

输出格式

请输出贝西能生成的最大整数。

说明/提示

在示例中，贝西首先合并第二个和第三个 1，得到序列 1 2 2，然后将两个 2 合并为 3。注意，合并前两个 1 并不是最优策略。

4
1
1
1
2

3

提示

In this example shown here, Bessie first merges the second and third 1s to obtain the sequence 1 2 2, and then she merges the 2s into a 3. Note that it is not optimal to join the first two 1s.