#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
#define endl "\n"
#define ll long long
#define IOS ios_base::sync_with_stdio(false); cin.tie(nullptr);
const int N = 2e5 + 5;
int sz[N];
bool seen_c[N];
int parent_c[N];
int color[N];
vector<int> adj[N];
void dfs_subtree(int u, int p) {
sz[u] = 1;
for (int v : adj[u]) {
if (v != p && !seen_c[v]) {
dfs_subtree(v, u);
sz[u] += sz[v];
}
}
return;
}
int dfs_centroid(int u, int p, int n) {
for (int v : adj[u]) {
if (v != p && !seen_c[v] && sz[v] > n / 2) {
return dfs_centroid(v, u, n);
}
}
return u;
}
vector<int> colors[N];
vector<int> q;
bool seen[N];
bool seen_subtree[N];
bool seen_color[N];
int parent[N];
vector<int> restore;
int ct, ans = N;
void dfs_depth(int u, int p, int cent) {
parent[u] = p;
if (color[u] == color[cent]) {
q.push_back(u);
seen[u] = true;
}
restore.push_back(u);
seen_subtree[u] = true;
for (int v : adj[u]) {
if (v != p && !seen_c[v]) {
dfs_depth(v, u, cent);
}
}
return;
}
void build(int u, int p) {
dfs_subtree(u, u);
int c = dfs_centroid(u, u, sz[u]);
if (p == -1) {
p = c;
}
parent_c[c] = p;
seen_c[c] = true;
parent[c] = c;
int can = 1;
ct = 0;
restore.push_back(c);
q.push_back(c);
seen[c] = true;
seen_subtree[c] = true;
seen_color[color[c]] = true;
for (int v : adj[c]) {
if (!seen_c[v]) {
dfs_depth(v, c, c);
}
}
if (q.size() != colors[color[c]].size()) {
can = 0;
} else {
while (q.size() && can) {
int u = q.back();
u = parent[u];
q.pop_back();
while (!seen[u] && can) {
seen[u] = true;
q.push_back(u);
if (!seen_color[color[u]]) {
ct++;
seen_color[color[u]] = true;
for (int v : colors[color[u]]) {
if (!seen_subtree[v]) {
can = 0;
break;
}
if (!seen[v]) {
seen[v] = true;
q.push_back(v);
}
}
}
u = parent[u];
}
}
}
if (can) {
ans = min(ans, ct);
}
q.clear();
for (int u : restore) {
seen[u] = false;
seen_color[color[u]] = false;
seen_subtree[u] = false;
}
restore.clear();
for (int v : adj[c]) {
if (!seen_c[v]) {
build(v, c);
}
}
return;
}
int main() {
IOS;
int n, k;
cin >> n >> k;
for (int i = 0; i < n - 1; i++) {
int u, v;
cin >> u >> v;
u--, v--;
adj[u].push_back(v);
adj[v].push_back(u);
}
for (int i = 0; i < n; i++) {
cin >> color[i];
colors[color[i]].push_back(i);
}
build(0, -1);
cout << ans;
return 0;
}
