UVA10801 电梯换乘 Lift Hopping

Description

[problemUrl]: https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=20&page=show_problem&problem=1742 [PDF](https://uva.onlinejudge.org/external/108/p10801.pdf) ![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA10801/0cbb7d34f46bb4d159da36c888a3bb419e194039.png)

Input Format

![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA10801/92bf4bc8a3ebf220c0627fcc9dfa4255914a00ba.png)

Output Format

![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA10801/f5d80a69aa87c0534aa09a5cf8534b3c541f74d2.png)