#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];
vector <int> a[mn], col[mn];
void pre_dfs(int u, int p){
st[u] = ++ timer_dfs;
euler[timer_dfs] = u;
for(auto v : a[u]){
if(v == p) continue;
pre_dfs(v, u);
euler[++ timer_dfs] = u;
}
ft[u] = timer_dfs;
}
int higher(int u, int v){
if(d[u] > d[v]) return v;
return u;
}
void build(){
for(int i = 1; i <= timer_dfs; i++) up[i][0] = euler[i];
for(int j = 1; (1 << j) <= timer_dfs; j++){
for(int i = 1; i + (1 << j) - 1 <= timer_dfs; i++){
up[i][j] = higher(up[i][j - 1], up[i + (1 << (j - 1))][j - 1]);
}
}
lg2[0] = -1;
for(int i = 1; i <= timer_dfs; i++) lg2[i] = lg2[i >> 1] + 1;
}
int lca(int u, int v){
if(u == 0) return v;
if(v == 0) return u;
if(st[u] > st[v]) swap(u, v);
int l = st[u], r = st[v], j = lg2[r - l + 1];
int x = higher(up[l][j], up[r - (1 << j) + 1][j]);
return x;
}
int dist(int u, int v){
int p = lca(u, v);
return d[u] + d[v] - 2 * d[p];
}
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';
}
}
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];
if(n <= 2000){
sub2000::sol();
return;
}
pre_dfs(1, 0); build();
}
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
