Rope Crisis in Ropeland!

题目描述

[problemUrl]: https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=13&page=show_problem&problem=1121 [PDF](https://uva.onlinejudge.org/external/101/p10180.pdf) ![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA10180/f785d533ff6ee2852dd7b4c02a80fb30171ae02c.png)

输入输出格式

输入格式

![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA10180/62ba37f9cfca6953baeba9cbb9141aea99387e72.png)

输出格式

![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA10180/56ba4ae3ec10b39314d726ccfa9f6bc428951318.png)

输入输出样例

输入样例 #1

2
1 1 -1 -1 1
1 1 -1 1 1

输出样例 #1

3.571
2.000