UVA786 Working with Relations

Description

[problemUrl]: https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=9&page=show_problem&problem=727 [PDF](https://uva.onlinejudge.org/external/7/p786.pdf) ![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA786/5263e87c11658f8a4c1ddb76d7b54ef3e90d2975.png)

Input Format

![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA786/f16ffd27a022d7f1fab52492bb462672bca5492d.png)

Output Format

![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA786/74ecfae4ca1562e4f71aa884d69d4e6341452371.png)