// #pragma GCC optimize("O3")
// #pragma GCC optimization("Ofast,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ll long long
#define FOR(i, l, r) for (int i = (l); i <= (r); i++)
#define FOD(i, r, l) for (int i = (r); i >= (l); i--)
#define fi first
#define se second
#define pii pair<int, int>
const ll mod = 1e9 + 7;
const int MAXN = 5e5 + 5;
const ll oo = 1e18 + 7;
const int base = 10;
int n, k;
vector<int> adj[MAXN];
int p[MAXN];
int h[MAXN], up[MAXN][20];
void dfs(int u, int p){
for(auto v:adj[u]){
if(v==p) continue;
h[v]=h[u]+1;
up[v][0]=u;
FOR(i, 1, 19){
up[v][i]=up[up[v][i-1]][i-1];
}
dfs(v, u);
}
}
int lca(int u, int v){
if(h[u]!=h[v]){
if(h[u]<h[v]){
swap(u, v);
}
int k=(h[u]-h[v]);
FOR(i, 0, 19){
if((k>>i)&1){
u=up[u][i];
}
}
}
if(u==v) return u;
FOD(i, 19, 0){
if(up[u][i]!=up[v][i]){
u=up[u][i];
v=up[v][i];
}
}
return up[u][0];
}
int par[MAXN];
int find(int u){
if(u==par[u]){
return u;
}
return par[u]=find(par[u]);
}
void join(int u, int v){
u=find(u);
v=find(v);
if(u==v){
return;
}
if(h[u]>h[v]) swap(u, v);
par[v]=u;
}
void merge1(int u, int p){
int uu=u;
while(h[uu]>=h[p]){
join(u, uu);
uu=up[find(uu)][0];
}
}
void merge(int u, int v){
int p=lca(u, v);
// cout << u << ' ' << v << ' ' << p << '\n';
merge1(u, p);
merge1(v, p);
}
int last[MAXN];
int cnt[MAXN];
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
// freopen("test.txt", "r", stdin);
// freopen("o2.out", "w", stdout);
if(fopen(".inp", "r")){
freopen(".inp", "r", stdin);
freopen(".out", "w", stdout);
}
cin >> n >> k;
FOR(i, 1, n-1){
int u, v;
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
FOR(i, 1, n){
cin >> p[i];
}
h[0]=-1;
dfs(1, 0);
FOR(i, 1, n){
par[i]=i;
}
FOR(i, 1, n){
if(last[p[i]]){
merge(last[p[i]], i);
}
last[p[i]]=i;
}
FOR(u, 1, n){
for(auto v:adj[u]){
if(find(u)!=find(v)){
cnt[v]++;
}
}
}
int ans=0;
FOR(i, 1, n){
if(cnt[i]==1){
ans++;
}
}
cout << (ans+1)/2;
return 0;
}
