Building designing

题目描述

[problemUrl]: https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=22&page=show_problem&problem=1980 [PDF](https://uva.onlinejudge.org/external/110/p11039.pdf) ![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA11039/6d32402ae71ac9268e8bd07b7ec1c1dde9d088fc.png)

输入输出格式

输入格式


![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA11039/d75e9dee0f6a5cd8097cc2e576bc075f1ebc5a56.png)

输出格式


![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA11039/d6c7e320cd2108d8b9b5cb90223e438a65c171b6.png)

输入输出样例

输入样例 #1

2
5
7
-2
6
9
-3
8
11
-9
2
5
18
17
-15
4

输出样例 #1

2
5