#include <bits/stdc++.h>
using namespace std;
const int N = 500'000 + 10;
int n, k;
vector<int> ad[N];
vector<int> state[N];
int st[N], ed[N], num;
int par[N];
void dfs(int u, int p = -1) {
st[u] = ++num;
for (const auto& v : ad[u]) {
if (v == p) continue;
par[v] = u;
dfs(v, u);
}
ed[u] = num;
}
inline bool anc(int u, int v) { return st[u] <= st[v] && ed[v] <= ed[u]; }
int id[N];
int root(int u) { return id[u] < 0 ? u : id[u] = root(id[u]); }
void join(int u, int v) {
u = root(u); v = root(v);
if (anc(v, u)) swap(u, v);
if (u == v) return;
id[u] += id[v];
id[v] = u;
}
int32_t main() {
cin.tie(0)->sync_with_stdio(0);
cin >> n >> k;
for (int i = 1; i < n; ++i) {
int u, v; cin >> u >> v;
ad[u].push_back(v);
ad[v].push_back(u);
}
for (int i = 1; i <= n; ++i) {
int s; cin >> s;
state[s].push_back(i);
}
dfs(par[1] = 1);
memset(id, -1, sizeof id);
for (int i = 1; i <= k; ++i) {
if (!state[i].size()) continue;
int u = state[i][0];
for (auto v : state[i]) {
while (!anc(u, v)) {
join(u, par[u]);
u = root(u);
}
while (v != u) {
join(v, par[v]);
v = root(v);
}
}
}
vector<pair<int, int>> edges;
for (int i = 1; i <= n; ++i) {
for (const auto& v : ad[i]) {
if (root(i) < root(v)) edges.push_back({root(i), root(v)});
}
ad[i].clear();
}
sort(edges.begin(), edges.end());
edges.erase(unique(edges.begin(), edges.end()), edges.end());
for (const auto& [u, v] : edges) {
ad[u].push_back(v);
ad[v].push_back(u);
}
int cntLeaf = 0;
for (int i = 1; i <= n; ++i) {
if (i == root(i)) cntLeaf += ((int)ad[i].size() == 1);
}
cout << max(0, cntLeaf - 1) << "\n";
}
