UVA12513 Safe Places

Description

[problemUrl]: https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=441&page=show_problem&problem=3958 [PDF](https://uva.onlinejudge.org/external/125/p12513.pdf) ![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA12513/ed75201d12af51ef5a51570d688dd795ac4f3a32.png)

Input Format

![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA12513/bbb70b911b8dd1454e8d38a80259d0ef37d66163.png)

Output Format

![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA12513/a7b1539a7a50cf4b0c69bf129c662faa32008049.png)