#include "bits/stdc++.h"
using namespace std;
#ifdef duc_debug
#include "bits/debug.h"
#else
#define debug(...)
#endif
const int maxn = 2e5 + 5;
int n, k;
vector<int> g[maxn];
vector<int> vc[maxn];
int c[maxn];
int color_sz[maxn];
vector<int> active;
int par[maxn], sz[maxn];
bool vis[maxn], del[maxn];
int res;
void re_dfs(int u, int prev) {
active.push_back(u);
sz[u] = 1;
for (auto v:g[u]) {
if (v == prev || del[v]) continue;
re_dfs(v, u);
sz[u] += sz[v];
}
}
int find_centroid(int u, int prev, int n) {
for (auto v:g[u]) {
if (v == prev || del[v]) continue;
if (sz[v] * 2 > n) {
return find_centroid(v, u, n);
}
}
return u;
}
int lab[maxn];
int find(int u) {
return lab[u] < 0 ? u : lab[u] = find(lab[u]);
}
void join(int u, int v) {
u = find(u), v = find(v);
if (u == v) return;
lab[u] += lab[v];
lab[v] = u;
}
void dfs_cen(int u, int prev) {
for (auto v:g[u]) {
if (v == prev || del[v]) continue;
par[v] = u;
dfs_cen(v, u);
}
}
void decompose(int u, int prev) {
active.clear();
re_dfs(u, prev);
int cen = find_centroid(u, prev, sz[u]);
for (auto x:active) {
lab[x] = -1;
vis[c[x]] = 0;
vc[c[x]].push_back(x);
}
par[cen] = 0;
dfs_cen(cen, 0);
queue<int> q;
vis[c[cen]] = 1;
q.push(c[cen]);
bool flag = 1;
int tot = 0;
while (!q.empty()) {
int cur_color = q.front();
q.pop();
++tot;
if (color_sz[cur_color] != (int)vc[cur_color].size()) {
flag = 0;
break;
}
for (auto vertex:vc[cur_color]) {
vertex = find(vertex);
if (par[vertex]) {
if (!vis[c[par[vertex]]]) {
q.push(c[par[vertex]]);
vis[c[par[vertex]]] = 1;
}
join(vertex, par[vertex]);
}
}
}
if (flag) {
res = min(res, tot - 1);
}
del[cen] = 1;
for (auto x:active) {
vc[c[x]].clear();
}
for (auto v:g[cen]) {
if (del[v] || v == prev) continue;
decompose(v, cen);
}
}
void solve() {
cin >> n >> k;
for (int i = 1; i < n; ++i) {
int u, v; cin >> u >> v;
g[u].push_back(v);
g[v].push_back(u);
}
for (int i = 1; i <= n; ++i) {
cin >> c[i];
++color_sz[c[i]];
}
res = n;
decompose(1, 0);
cout << res;
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
solve();
return 0;
}
