UVA12969 Foes of Friends

Description

[problemUrl]: https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=862&page=show_problem&problem=4848 [PDF](https://uva.onlinejudge.org/external/129/p12969.pdf) ![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA12969/4bc34cb25fecd195e32cbcfceb4ce11fd10a4e94.png)

Input Format

![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA12969/9c453e6d130703ea377f12b48553c8dc6ce40373.png)

Output Format

![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA12969/5108b8416ae362dc2a3d1c656fd5b2dc4dc5b5fc.png)