#include <algorithm>
#include <iostream>
#include <vector>
#include <map>
using namespace std;
const int NMAX = 5e5;
const int LGMAX = 19;
vector <int> adj[NMAX + 1];
int s[NMAX + 1];
int lvl[NMAX + 1];
int dp[NMAX + 1][LGMAX + 1];
void dfs1(int node, int parent){
lvl[node] = lvl[parent] + 1;
dp[node][0] = parent;
for(int child : adj[node]){
if(child != parent){
dfs1(child, node);
}
}
}
int LCA(int a, int b){
if(lvl[a] < lvl[b]){
swap(a, b);
}
int diff = lvl[a] - lvl[b];
for(int i = LGMAX; i >= 0; i--){
if(diff & (1 << i)){
a = dp[a][i];
}
}
if(a == b){
return a;
}
for(int i = LGMAX; i >= 0; i--){
if(dp[a][i] != dp[b][i]){
a = dp[a][i];
b = dp[b][i];
}
}
return dp[a][0];
}
int glca[NMAX + 1];
int bad[NMAX + 1];
int dfs2(int node, int parent){
int mini = lvl[glca[s[node]]];
for(int child : adj[node]){
if(child != parent){
mini = min(mini, dfs2(child, node));
}
}
if(mini >= lvl[node]){
bad[node] = parent;
}
return mini;
}
int Id = 0;
int id[NMAX + 1];
void dfs3(int node, int parent){
if(bad[node] == parent){
id[node] = ++Id;
}else{
id[node] = id[parent];
}
for(int child : adj[node]){
if(child != parent){
dfs3(child, node);
}
}
}
vector <int> T[NMAX + 1];
void dfs4(int node, int parent){
for(int child : adj[node]){
if(child != parent){
if(id[child] != id[node]){
T[id[node]].push_back(id[child]);
T[id[child]].push_back(id[node]);
}
dfs4(child, node);
}
}
}
int main(){
int n, k;
cin >> n >> k;
for(int i = 1; i <= n - 1; i++){
int a, b;
cin >> a >> b;
adj[a].push_back(b);
adj[b].push_back(a);
}
for(int i = 1; i <= n; i++){
cin >> s[i];
}
dfs1(1, 0);
for(int j = 1; (1 << j) <= n; j++){
for(int i = 1; i <= n; i++){
dp[i][j] = dp[dp[i][j - 1]][j - 1];
}
}
for(int i = 1; i <= n; i++){
if(glca[s[i]] == 0){
glca[s[i]] = i;
}else{
glca[s[i]] = LCA(glca[s[i]], i);
}
}
dfs2(1, 0);
dfs3(1, 0);
dfs4(1, 0);
int leafs = 0;
for(int i = 1; i <= Id; i++){
sort(T[i].begin(), T[i].end());
T[i].erase(unique(T[i].begin(), T[i].end()), T[i].end());
if((int)T[i].size() == 1){
leafs++;
}
}
cout << (leafs / 2) + (leafs % 2) << '\n';
return 0;
}
/*
5 4
1 2
2 3
3 4
3 5
1
2
1
3
4
*/
