#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define x first
#define y second
ll N, K, A[200005], Tot[200005], S[200005], vis[200005];
vector<ll> T[200005];
ll Size(ll u, ll p){
S[u] = 1;
for(auto v : T[u]){
if(v != p && !vis[v]) S[u] += Size(v, u);
}
return S[u];
}
ll Cent(ll u, ll p, ll n){
for(auto v : T[u]){
if(v != p && !vis[v] && S[v] > n / 2) return Cent(v, u, n);
}
return u;
}
ll Par[200005], chk[200005], Ans = 1e18;
vector<ll> U[200005];
void dfs(ll u, ll p, vector<ll> &V, vector<ll> &Del){
Par[u] = p;
V.push_back(A[u]); Del.push_back(u);
U[A[u]].push_back(u);
for(auto v : T[u]){
if(v == p || vis[v]) continue;
dfs(v, u, V, Del);
}
}
void dnc(ll _u){
ll u = Cent(_u, -1, Size(_u, -1));
vis[u] = 1;
vector<ll> V, Del;
dfs(u, u, V, Del);
sort(V.begin(), V.end());
V.erase(unique(V.begin(), V.end()), V.end());
ll ok = 1;
for(auto e : V){
if(U[e].size() != Tot[e]){
ok = 0; break;
}
}
if(ok){
queue<ll> Q;
ll c = 0;
for(auto i : U[A[u]]){
chk[i] = 1; Q.push(i);
}
while(!Q.empty()){
ll k = Q.front(); Q.pop();
if(k == u) continue;
k = Par[k];
if(chk[k] || U[A[k]].empty()) continue;
for(auto i : U[A[k]]){
f = 1, chk[i] = 1;
Q.push(i);
}
U[A[k]].clear();
c += f;
chk[k] = 1;
Q.push(k);
}
Ans = min(Ans, c);
}
for(auto i : Del){
chk[i] = 0; U[A[i]].clear();
}
for(auto v : T[u]){
if(!vis[v]) dnc(v);
}
}
int main(){
cin.tie(0) -> sync_with_stdio(0);
cin >> N >> K;
for(ll i = 1; i < N; i++){
ll u, v; cin >> u >> v;
T[u].push_back(v); T[v].push_back(u);
}
for(ll i = 1; i <= N; i++){
cin >> A[i];
Tot[A[i]]++;
}
dnc(1);
cout << Ans;
}
