UVA11639 Guard the Land

Description

[problemUrl]: https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=78&page=show_problem&problem=2686 [PDF](https://uva.onlinejudge.org/external/116/p11639.pdf) ![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA11639/6ffb015599d9d7714ac4e3074e1923d81e1865e0.png)

Input Format

![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA11639/e4ad59e4972bf7704d2f30470420823aec707b08.png)

Output Format

![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA11639/b4462f40497b0eab767c1173c4fd6aedf331f766.png)