#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define fi first
#define se second
#define vi vector<int>
#define vll vector<long long>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
mt19937_64 rng64(chrono::high_resolution_clock::now().time_since_epoch().count());
inline int rand(int l,int r){return uniform_int_distribution<int>(l, r)(rng);}
inline ll rand(ll l,ll r){return uniform_int_distribution<ll>(l, r)(rng64);}
#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif
struct custom_hash {
static uint64_t splitmix64(uint64_t x) {
x += 0x9e3779b97f4a7c15;
x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
return x ^ (x >> 31);
}
size_t operator()(uint64_t x) const {
static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
return splitmix64(x + FIXED_RANDOM);
}
};
struct pair_hash{
size_t operator()(const pair<int,int>&x)const{
return hash<long long>()(((long long)x.first)^(((long long)x.second)<<32));
}
};
const int MAXN = 2e5 + 7;
const int INF = 1e9;
vi g[MAXN];
vi pos[MAXN];
int C[MAXN];
int blocked_color[MAXN];
int blocked[MAXN];
int parent[MAXN];
int used[MAXN];
int sz[MAXN];
int subtree[MAXN];
int usedCol[MAXN];
int idCol[MAXN];
int n, m;
int ans = INF;
vi comp;
void dfsInit(int v, int p){
comp.pb(v);
sz[v] = 1;
for(auto u : g[v]){
if(u == p || blocked[u]){
continue;
}
dfsInit(u, v);
sz[v] += sz[u];
}
}
int findCentroid(int v, int p, int N){
for(auto u : g[v]){
if(blocked[u] || u == p){
continue;
}
if(2 * sz[u] >= N){
return findCentroid(u, v, N);
}
}
return v;
}
void dfs2(int v, int p, int sub){
subtree[v] = sub;
parent[v] = p;
used[v] = 0;
idCol[C[v]] = -1;
usedCol[C[v]] = 0;
for(auto u : g[v]){
if(u == p || blocked[u]){
continue;
}
dfs2(u, v, sub);
}
}
void centroid_decomposition(int v){
comp.clear();
dfsInit(v, v);
int centroid = findCentroid(v, v, sz[v]);
used[centroid] = 0;
for(auto u : g[centroid]){
if(blocked[u]){
continue;
}
dfs2(u, centroid, u);
}
usedCol[C[centroid]] = 1;
vi vec = {};
bool flag = 1;
int res = 0;
if(blocked_color[C[centroid]]){
flag = 0;
}else{
usedCol[C[centroid]] = 1;
for(auto ele : pos[C[centroid]]){
vec.pb(ele);
}
}
while(sz(vec) && flag){
int curr = vec.back();
vec.pop_back();
while(!used[curr]){
used[curr] = 1;
if(blocked_color[C[curr]]){
flag = 0;
break;
}
if(!usedCol[C[curr]]){
usedCol[C[curr]] = 1;
//cerr << "ADD: " << curr << ' ' << C[curr] << '\n';
res++;
for(auto ele : pos[C[curr]]){
if(!used[ele]){
vec.pb(ele);
}
}
}
if(curr == centroid){
break;
}
curr = parent[curr];
}
}
// cerr << "======\n";
// cerr << centroid << '\n';
// debug(comp);
// cerr << res << ' ' << flag << '\n';
// for(auto ele : comp){
// cerr << ele << ' ' << used[ele] << '\n';
// }
if(flag){
ans = min(ans, res);
}
blocked_color[C[centroid]] = 1;
for(auto ele : comp){
if(idCol[C[ele]] == -1){
idCol[C[ele]] = subtree[ele];
}
if(idCol[C[ele]] != subtree[ele]){
blocked_color[C[ele]] = 1;
}
}
blocked[centroid] = 1;
for(auto u : g[centroid]){
if(!blocked[u]){
centroid_decomposition(u);
}
}
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
cin >> n >> m;
for(int i = 1; i < n; i++){
int a, b;
cin >> a >> b;
g[a].pb(b);
g[b].pb(a);
}
for(int i = 1; i <= n; i++){
cin >> C[i];
pos[C[i]].pb(i);
}
centroid_decomposition(1);
cout << ans << '\n';
return 0;
}
