#include <bits/stdc++.h>
#ifdef local
#define debug(a...) qqbx(#a, a)
template <typename ...T> void qqbx(const char *s, T ...a) {
int cnt = sizeof...(T);
((std::cerr << "\033[1;32m(" << s << ") = (") , ... , (std::cerr << a << (--cnt ? ", " : "\033[0m)\n")));
}
#define safe std::cerr<<__PRETTY_FUNCTION__<<" line "<<__LINE__<<" safe\n"
#else
#define debug(...) ((void)0)
#define safe ((void)0)
#endif // local
#define all(v) begin(v),end(v)
#define pb emplace_back
#define sort_uni(v) sort(all(v)), v.erase(unique(all(v)), v.end())
using namespace std;
using ll = int64_t;
template <typename T> using min_heap = priority_queue<T, vector<T>, greater<T>>;
const ll INF = 1e18;
const int maxn = 500025, inf = 1e9;
struct Dsu {
vector<int> pa, rk;
Dsu(int n) : pa(n), rk(n) { iota(all(pa), 0); }
int anc(int x) { return x==pa[x] ? x : pa[x] = anc(pa[x]); }
bool join(int x, int y) {
if ((x=anc(x)) == (y=anc(y))) return false;
if (rk[x] < rk[y]) swap(x, y);
return pa[y] = x, rk[x] != rk[y] || ++rk[x];
}
} dsu(maxn);
vector<int> g[maxn], adj[maxn];
int color[maxn];
int cnt[maxn];
map<int,int> mp[maxn];
void join(map<int,int> &a, map<int,int> &b) {
if (a.size() < b.size()) a.swap(b);
for (auto [x, y]: b) {
a[x] += y;
if (a[x] == cnt[x]) a.erase(x);
}
b.clear();
}
void dfs(int i, int p) {
for (int j: g[i]) {
if (j == p) continue;
dfs(j, i);
join(mp[i], mp[j]);
}
mp[i][color[i]] += 1;
if (mp[i][color[i]] == cnt[color[i]])
mp[i].erase(color[i]);
debug(i);
for (auto [a, b]: mp[i])
debug(a, b);
if (!mp[i].empty())
dsu.join(i, p);
}
signed main() {
ios_base::sync_with_stdio(0), cin.tie(0);
int n, k;
cin >> n >> k;
for (int i = 1; i < n; i++) {
int a, b;
cin >> a >> b;
g[a].emplace_back(b);
g[b].emplace_back(a);
}
for (int i = 1; i <= n; i++) cin >> color[i], ++cnt[color[i]];
dfs(1, 0);
vector<int> deg(n + 1);
for (int i = 1; i <= n; i++) {
for (int j: g[i]) {
int a = dsu.anc(i);
int b = dsu.anc(j);
if (a != b)
adj[a].push_back(b);
}
}
for (int i = 1; i <= n; i++) sort_uni(adj[i]);
int leaf = 0;
for (int i = 1; i <= n; i++) {
int deg = adj[i].size();
debug(deg);
if (deg == 1) ++leaf;
}
debug(leaf);
cout << (leaf + 1) / 2 << '\n';
}
