Codeforces Round 603 (Div. 2)
F
Economic Difficulties
Codeforces
2400
原题
← E→
翻译中…

An electrical grid in Berland palaces consists of 2 grids: main and reserve. Wires in palaces are made of expensive material, so selling some of them would be a good idea!

翻译中…

Each grid (main and reserve) has a head node (its number is $1$). Every other node gets electricity from the head node. Each node can be reached from the head node by a unique path. Also, both grids have exactly $n$ nodes, which do not spread electricity further.

翻译中…

In other words, every grid is a rooted directed tree on $n$ leaves with a root in the node, which number is $1$. Each tree has independent enumeration and nodes from one grid are not connected with nodes of another grid.

翻译中…

Also, the palace has $n$ electrical devices. Each device is connected with one node of the main grid and with one node of the reserve grid. Devices connect only with nodes, from which electricity is not spread further (these nodes are the tree's leaves). Each grid's leaf is connected with exactly one device.

翻译中…

image In this example the main grid contains $6$ nodes (the top tree) and the reserve grid contains $4$ nodes (the lower tree). There are $3$ devices with numbers colored in blue.

翻译中…

It is guaranteed that the whole grid (two grids and $n$ devices) can be shown in this way (like in the picture above):

翻译中…
  • main grid is a top tree, whose wires are directed 'from the top to the down',
  • reserve grid is a lower tree, whose wires are directed 'from the down to the top',
  • devices — horizontal row between two grids, which are numbered from $1$ to $n$ from the left to the right,
  • wires between nodes do not intersect.
翻译中…

Formally, for each tree exists a depth-first search from the node with number $1$, that visits leaves in order of connection to devices $1, 2, \dots, n$ (firstly, the node, that is connected to the device $1$, then the node, that is connected to the device $2$, etc.).

翻译中…

Businessman wants to sell (remove) maximal amount of wires so that each device will be powered from at least one grid (main or reserve). In other words, for each device should exist at least one path to the head node (in the main grid or the reserve grid), which contains only nodes from one grid.

翻译中…

Input

翻译中…

The first line contains an integer $n$ ($1 \le n \le 1000$) — the number of devices in the palace.

翻译中…

The next line contains an integer $a$ ($1 + n \le a \le 1000 + n$) — the amount of nodes in the main grid.

翻译中…

Next line contains $a - 1$ integers $p_i$ ($1 \le p_i \le a$). Each integer $p_i$ means that the main grid contains a wire from $p_i$-th node to $(i + 1)$-th.

翻译中…

The next line contains $n$ integers $x_i$ ($1 \le x_i \le a$) — the number of a node in the main grid that is connected to the $i$-th device.

翻译中…

The next line contains an integer $b$ ($1 + n \le b \le 1000 + n$) — the amount of nodes in the reserve grid.

翻译中…

Next line contains $b - 1$ integers $q_i$ ($1 \le q_i \le b$). Each integer $q_i$ means that the reserve grid contains a wire from $q_i$-th node to $(i + 1)$-th.

翻译中…

The next line contains $n$ integers $y_i$ ($1 \le y_i \le b$) — the number of a node in the reserve grid that is connected to the $i$-th device.

翻译中…

It is guaranteed that each grid is a tree, which has exactly $n$ leaves and each leaf is connected with one device. Also, it is guaranteed, that for each tree exists a depth-first search from the node $1$, that visits leaves in order of connection to devices.

翻译中…

Output

翻译中…

Print a single integer — the maximal amount of wires that can be cut so that each device is powered.

翻译中…

Note

翻译中…

For the first example, the picture below shows one of the possible solutions (wires that can be removed are marked in red):

翻译中…

image

翻译中…

The second and the third examples can be seen below:

翻译中…

image

翻译中…

样例

Input #1
3
6
4 1 1 4 2
6 5 3
4
1 1 1
3 4 2
Output #1
5
InputCopy OutputCopy
Input #2
4
6
4 4 1 1 1
3 2 6 5
6
6 6 1 1 1
5 4 3 2
Output #2
6
InputCopy OutputCopy
Input #3
5
14
1 1 11 2 14 14 13 7 12 2 5 6 1
9 8 3 10 4
16
1 1 9 9 2 5 10 1 14 3 7 11 6 12 2
8 16 13 4 15
Output #3
17
InputCopy OutputCopy
题目信息
题号
1263F
时间限制
3 s
内存限制
256 MB
标签
数据结构
DFS 及类似
动态规划
网络流
图论
树

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。