UVA12688 Spanning trees in a secure lock pattern

Description

[problemUrl]: https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=602&page=show_problem&problem=4426 [PDF](https://uva.onlinejudge.org/external/126/p12688.pdf) ![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA12688/558e40850367d2011c8887988efea0f94bd75397.png)

Input Format

![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA12688/f599591fe96ed30a24f3d3db00920cb282ca538f.png)

Output Format

![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA12688/6ea054cf31b5048aed51304db35b5d0df7a5415e.png)