in
8
2
1
1
2
4
2
3
4

out
4

https://www.luogu.com.cn/blog/Manjusaka/solution-p3146

https://www.luogu.com.cn/blog/Tony102/solution-p3146

https://www.luogu.com.cn/blog/expect2004/solution-p3146

均输出 5