#include <bits/stdc++.h>
using i64 = long long;
#ifdef DEBUG
#include "debug.h"
#else
#define debug(...) void(23)
#endif
struct DSU {
std::vector<int> f, siz;
DSU(int n) : f(n), siz(n, 1) {
std::iota(f.begin(), f.end(), 0);
}
int get(int x) {
while (x != f[x]) {
x = f[x] = f[f[x]];
}
return x;
}
bool unite(int a, int b) {
a = get(a), b = get(b);
if (a == b) {
return false;
}
f[a] = b;
siz[b] += siz[a];
return true;
}
bool same(int a, int b) {
return get(a) == get(b);
}
int size(int x) {
return siz[get(x)];
}
};
int main() {
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr);
int N, K;
std::cin >> N >> K;
std::vector<std::vector<int>> adj(N);
for (int i = 1; i < N; ++i) {
int U, V;
std::cin >> U >> V;
--U, --V;
adj[U].emplace_back(V);
adj[V].emplace_back(U);
}
std::vector<int> C(N);
for (int i = 0; i < N; ++i) {
std::cin >> C[i];
--C[i];
}
std::vector<std::vector<int>> g(K);
for (int i = 0; i < N; ++i) {
g[C[i]].emplace_back(i);
}
int tim = 0;
std::vector<int> par(N);
std::vector<int> dep(N);
std::vector<int> tin(N);
auto dfs = [&](auto&& self, int v) -> void {
tin[v] = tim++;
for (auto u : adj[v]) {
if (u == par[v]) {
continue;
}
dep[u] = dep[v] + 1;
par[u] = v;
self(self, u);
}
};
dfs(dfs, 0);
DSU dsu(N);
for (int i = 0; i < K; ++i) {
std::sort(g[i].begin(), g[i].end(), [&](auto lhs, auto rhs) {
return tin[lhs] < tin[rhs];
});
for (int j = 0; j + 1 < int(g[i].size()); ++j) {
int v = g[i][j];
int u = g[i][j + 1];
while (v != u) {
if (dep[v] < dep[u]) {
std::swap(u, v);
}
dsu.unite(v, par[v]);
v = dsu.get(par[v]);
}
}
}
if (dsu.size(0) == N) {
std::cout << "0\n";
return 0;
}
std::vector<std::vector<int>> ndj(N);
for (int i = 0; i < N; ++i) {
for (auto j : adj[i]) {
if (!dsu.same(i, j)) {
ndj[dsu.get(i)].emplace_back(dsu.get(j));
}
}
}
int cnt = 0;
for (int i = 0; i < N; ++i) {
cnt += int(ndj[i].size()) == 1;
}
int ans = (cnt + 1) / 2;
std::cout << ans << '\n';
return 0;
}
