题目描述
Problem Description
Given a tree with $ N $ vertices numbered from $ 1 $ to $ N $. The $ i $ -th edge connects vertex $ A_i $ and vertex $ B_i $.
From this graph, remove some (possibly zero) edges and vertices to form a tree that includes all the specified $ K $ vertices, $V_1, \ldots, V_K$. Find the minimum number of vertices in such a tree.
Input Format
The input is given from the standard input in the following format:
$ N $ $ K $ $ A_1 $ $ B_1 $ $\vdots$ $ A_{N-1} $ $ B_{N-1} $ $ V_1 $ $\ldots$ $ V_K $
Output Format
Output the answer.
Sample Input and Output
Sample Input #1
7 3
1 2
1 3
2 4
2 5
3 6
3 7
1 3 5
Sample Output #1
4
Sample Input #2
4 4
3 1
1 4
2 1
1 2 3 4
Sample Output #2
4
Sample Input #3
5 1
1 4
2 3
5 2
1 2
1
Sample Output #3
1
Notes/Hints
Constraints
- $1 \leq K \leq N \leq 2 \times 10^5$
- $1 \leq A_i, B_i \leq N$
- $1 \leq V_1 < V_2 < \ldots < V_K \leq N$
- The given graph is a tree.
- All inputs are integers.
Sample Explanation 1
The given tree is as shown in the left diagram below, and the tree with the minimum number of vertices that includes all vertices $ 1, 3, 5 $ is as shown in the right diagram.

输入格式
见题面 Input 部分
输出格式
见题面 Output 部分