/*
Author: Nguyen Chi Thanh - High School for the Gifted - VNU.HCM (i2528)
*/
#include <bits/stdc++.h>
using namespace std;
/* START OF TEMPALTE */
// #define int long long
#define ll long long
#define ull unsigned long long
#define ld long double
#define pii pair<int, int>
#define pll pair<ll, ll>
#define fi first
#define se second
#define popcount __builtin_popcountll
#define all(x) (x).begin(), (x).end()
#define BIT(x, i) (((x) >> (i)) & 1)
#define MASK(x) (1ll << (x))
#define SZ(a) ((int32_t)a.size())
#define debug(a, l, r) {for (int _i = (l); _i <= (r); ++_i) cout << (a)[_i] << ' '; cout << '\n';}
template<class X, class Y>
bool minimize(X &x, const Y &y) {
if (x > y) {
x = y;
return true;
} else return false;
}
template<class X, class Y>
bool maximize(X &x, const Y &y) {
if (x < y) {
x = y;
return true;
} else return false;
}
/* END OF TEMPALTE */
struct DSU {
int n;
vector<int> par, sz;
DSU() {}
DSU(int _n) : n(_n), par(n + 5), sz(n + 5, 1) {
iota(all(par), 0);
}
int findSet(int x) {
while (x != par[x])
x = par[x] = par[par[x]];
return x;
}
bool unite(int x, int y) {
x = findSet(x); y = findSet(y);
if (x == y) return 0;
if (sz[x] < sz[y]) swap(x, y);
sz[x] += sz[y];
par[y] = x;
return 1;
}
bool same(int u, int v) {
return findSet(u) == findSet(v);
}
};
const int MAXN = 5e5 + 5;
const int LG = 19;
int n, k, up[LG + 1][MAXN], depth[MAXN], farthest[MAXN], deg[MAXN];
vector<int> adj[MAXN], col[MAXN];
vector<pii> edges;
DSU dsu;
void init() {
cin >> n >> k;
for (int i = 1; i < n; ++i) {
int u, v; cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
edges.push_back({u, v});
}
dsu = DSU(n);
for (int i = 1; i <= n; ++i) {
int s; cin >> s;
col[s].push_back(i);
farthest[i] = i;
}
}
void dfsLCA(int u, int par = 0) {
up[0][u] = par;
for (int j = 1; j <= LG; ++j)
up[j][u] = up[j - 1][up[j - 1][u]];
for (int v : adj[u]) {
if (v == par) continue;
depth[v] = depth[u] + 1;
dfsLCA(v, u);
}
}
int lift(int u, int k) {
for (int j = 0; j <= LG; ++j)
if (BIT(k, j)) u = up[j][u];
return u;
}
int lca(int u, int v) {
if (depth[u] > depth[v]) swap(u, v);
int diff = depth[v] - depth[u];
v = lift(v, diff);
if (u == v) return u;
for (int j = LG; j >= 0; --j) {
if (up[j][u] != up[j][v]) {
u = up[j][u];
v = up[j][v];
}
}
return up[0][u];
}
void dfsBuild(int u, int par = 0) {
for (int v : adj[u]) {
if (v == par) continue;
dfsBuild(v, u);
farthest[u] = lca(farthest[u], farthest[v]);
}
if (u != 1 && u != farthest[u])
dsu.unite(u, par);
}
void solve() {
dfsLCA(1);
for (int c = 1; c <= k; ++c) {
if (!SZ(col[c])) continue;
int far = col[c][0];
for (auto u : col[c]) far = lca(far, u);
for (auto u : col[c]) farthest[u] = far;
}
dfsBuild(1);
for (auto &e : edges) {
int u = e.fi, v = e.se;
int x = dsu.findSet(u), y = dsu.findSet(v);
if (x == y) continue;
deg[x]++; deg[y]++;
}
int numLeaves = 0;
for (int i = 1; i <= n; ++i)
if (deg[i] == 1) ++numLeaves;
int ans = (numLeaves + 1) / 2;
cout << ans;
}
signed main() {
#ifdef NCTHANH
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
ios_base::sync_with_stdio(0);
cin.tie(nullptr); cout.tie(nullptr);
init();
solve();
return 0;
}
