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A15850 | Tree Cutting

时间限制1s
内存限制256MB
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题目描述

You are given a tree with $n$ vertices.

A hero $k$ times do the following operation:

- Choose some edge.
- Remove it.
- Take one of the two remaining parts and delete it.
- Write the number of vertices in the remaining part.

You are given an initial tree and the a sequence of written numbers. Find the number of ways to make operations such that the written numbers are equal to the given numbers. Due to the answer can be big, find it by modulo $998\,244\,353$ . Two ways are considered different, if on some operation edge or remaining part are selected differently.

输入格式

The first line contains a single integer $n$ ( $2 \leq n \leq 5000$ ) — the number of vertices.

Each of the next $n-1$ lines contains two integers $s$ , $f$ ( $1 \leq s, f \leq n$ , $s \neq f$ ) — description of edge $(s, f)$ .

Next line contains a single integer $k$ ( $1 \leq k \leq \min{(6, n - 1)}$ ) — the number of operations.

Next line contains $k$ integers $s_1, s_2, \ldots, s_k$ ( $n > s_1 > s_2 > \ldots > s_k \geq 1$ ) — written numbers.

输出格式

Print a single integer — the answer to the problem by modulo $998\,244\,353$ .

输入输出样例

输入 #1
3
1 2
2 3
2
2 1
输出 #1
4
输入 #2
7
2 1
3 2
4 1
5 3
6 4
7 4
2
4 2
输出 #2
2
输入 #3
7
1 2
1 3
1 4
2 5
3 6
4 7
1
2
输出 #3
3
输入 #4
7
1 2
1 3
1 4
2 5
3 6
4 7
4
6 5 2 1
输出 #4
24
输入 #5
8
1 2
2 3
3 4
3 5
3 6
3 7
3 8
2
7 4
输出 #5
0
C++ 编辑器
输入
输出