#include<bits/stdc++.h>
using namespace std;
#define int long long
#define pii pair<int, int>
int n, k;
const int MAX_N = 500'000;
const int MAX_K = 500'000;
const int INF = 1e18;
int res = 0;
vector<int> adj[MAX_N];
vector<int> mem[MAX_N];
int group[MAX_N];
int anc[MAX_N];
int group_lca[MAX_K];
int depth[MAX_N];
void dfs(int u, int a, int d){
//cout<<"dfs "<<u<<endl;
anc[u] = a;
depth[u] = d;
for(auto v: adj[u]){
if(v!=a){
dfs(v, u, d+1);
}
}
}
int bl[19][MAX_N];
void build_bl(){
for(int i = 0; i<n; i++){
bl[0][i] =anc[i];
}
for(int i = 1; i<19; i++){
for(int j = 0; j<n; j++){
bl[i][j] = bl[i-1][bl[i-1][j]];
}
}
}
int lca(int a, int b){
if(a==-1){
return b;
}
if(b==-1){
return a;
}
if(depth[a]>depth[b]){
return lca(b, a);
}
for(int step = 18; step>=0; step--){
if(depth[bl[step][b]]>=depth[a]){
b = bl[step][b];
}
}
if(a==b){
return a;
}
for(int step = 18; step>=0; step--){
if(bl[step][a] != bl[step][b]){
a = bl[step][a];
b= bl[step][b];
}
}
return bl[0][a];
}
bool is_free[MAX_N];
int nbf = 0;
int dfs2(int u){
int min_d = INF;
min_d= min(min_d, depth[group_lca[group[u]]]);
for(auto v: adj[u]){
if(v!= anc[u]){
min_d= min(min_d, dfs2(v));
}
}
if(min_d >= depth[u]){
is_free[u] = true;
nbf++;
}
return min_d;
}
pii dfs3(int u){
pii s= pii(0, 0);
for(auto v: adj[u]){
if(v!=anc[u]){
auto r=dfs3(v);
s.first += r.first;
s.second += r.second;
}
}
if((s.second == nbf-1|| s.first==0) && is_free[u]){
res++;
}
//cout<<3<<" "<<u<<" "<<s<<endl;
if(is_free[u]){
s.first = 1;
s.second++;
}
return s;
}
signed main(){
cin>>n>>k;
fill(group_lca, group_lca + MAX_K, -1);
for(int i = 0; i<n-1; i++){
int a, b;
cin>>a>>b;
adj[a-1].push_back(b-1);
adj[b-1].push_back(a-1);
}
dfs(0, 0, 0);
build_bl();
for(int i = 0; i<n; i++){
cin>>group[i];
group[i]--;
}
for(int i = 0; i<n; i++){
group_lca[group[i]] = lca(group_lca[group[i]], i);
}
dfs2(0);
is_free[0] = false;
nbf--;
dfs3(0);
cout<<(res+1)/2<<endl;
}
