#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define pii pair<int, int>
#define all(a) a.begin(), a.end()
using namespace std;
#ifdef LOCAL
#include "C:\Users\Dell\Downloads\template\template\icpc-notebook\Utilities\debug.h"
#else
#define debug(...) 42
#endif
const int mn = 5e5 + 5, mod = 1e9 + 7, inf = 2e9;
int n, k, c[mn], up[mn][20], d[mn], st[mn], ft[mn], euler[mn], timer_dfs = 0, lg2[mn], Megumi[mn];
vector <int> a[mn], col[mn];
namespace sub2000 {
int on[2005], vis[2005], par[2005], d[2005];
void dfs(int u, int p){
for(auto v : a[u]){
if(v == p) continue;
par[v] = u;
d[v] = d[u] + 1;
dfs(v, u);
}
}
void sol(){
for(int i = 1; i <= n; i++){
col[c[i]].push_back(i);
}
int min_val = inf;
for(int i = 1; i <= n; i++){
queue <int> q;
memset(on, 0, sizeof(on)); memset(vis, 0, sizeof(vis)); memset(par, 0, sizeof(par));
on[c[i]] = 1, vis[i] = 1;
for(auto u : col[c[i]]) q.push(u);
dfs(i, 0);
debug(i, col[c[i]]);
int res = 0;
while(q.size()){
int u = q.front();
q.pop();
while(d[u] > d[i]){
if(vis[u]) break;
vis[u] = 1;
u = par[u];
debug(u, i);
if(!on[c[u]]){
on[c[u]] = 1;
res ++;
for(auto v : col[c[u]]) q.push(v);
}
}
}
debug(min_val, res);
min_val = min(min_val, res);
}
cout << min_val << '\n';
}
}
namespace full{
int ans = inf, d[mn], vis[mn], par[mn], on[mn], sz[mn], cc[mn];
void pre_dfs(int u, int p){
sz[u] = 1;
for(auto v : a[u]){
if(v == p || on[v]) continue;
par[v] = u, d[v] = d[u] + 1;
pre_dfs(v, u);
sz[u] += sz[v];
}
}
int find(int u, int p, int ovr_sz){
for(auto v : a[u]){
if(v == p || on[v]) continue;
if(sz[v] * 2 > ovr_sz) return find(v, u, ovr_sz);
}
return u;
}
vector <int> all;
void collect(int u, int p){
all.push_back(u);
d[u] = d[p] + 1;
par[u] = p;
for(auto v : a[u]){
if(v == p || on[v]) continue;
collect(v, u);
}
}
void decompose(int cen){
pre_dfs(cen, 0);
cen = find(cen, 0, sz[cen]);
on[cen] = 1, par[cen] = 0, d[cen] = 0;
collect(cen, 0);
for(auto v : all){
col[c[v]].push_back(v);
}
queue <int> q;
cc[c[cen]] = 1, vis[cen] = 1;
for(auto u : col[c[cen]]) q.push(u);
// cerr << "Centroid " << cen << '\n';
debug(col[c[cen]]);
debug(all);
int res = 0;
while(q.size()){
int u = q.front();
q.pop();
debug(u, cen);
if((int) col[c[u]].size() < Megumi[c[u]]){
res = inf;
break;
}
while(d[u] > d[cen]){
if(vis[u]) break;
vis[u] = 1, u = par[u];
if(!cc[c[u]]){
cc[c[u]] = 1;
res ++;
for(auto v : col[c[u]]) q.push(v);
}
}
}
ans = min(ans, res);
debug(cen, ans);
for(auto v : all){
col[c[v]].clear();
cc[c[v]] = vis[v] = 0;
}
all.clear();
for(auto v : a[cen]){
if(on[v]) continue;
decompose(v);
}
}
void sol(){
decompose(1);
cout << ans << '\n';
}
}
void solve() {
cin >> n >> k;
for(int i = 1; i < n; i++) {
int u, v; cin >> u >> v;
a[u].push_back(v);
a[v].push_back(u);
}
for(int i = 1; i <= n; i++){
cin >> c[i];
Megumi[c[i]] ++;
}
full::sol();
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr); cout.tie(nullptr);
#define task "Kawabata"
if (fopen(task".INP", "r")) {
freopen(task".INP", "r", stdin);
freopen(task".OUT", "w", stdout);
}
int t = 1;
// cin >> t;
while (t--) solve();
return 0;
}
// Don't wanna lose anymore T_T
// Never let me go - Kazuo Ishiguro
