#include <bits/stdc++.h>
using namespace std;
#define pii pair<int, int>
#define ff first
#define ss second
#define pb push_back
const int mxN = 5e5 + 1;
vector<int> adj[mxN];
int a[mxN];
vector<int> state[mxN];
int n, k;
void Input() {
cin >> n >> k;
for (int i = 0; i < n - 1; i++) {
int u, v;
cin >> u >> v;
adj[u].pb(v);
adj[v].pb(u);
}
for (int i = 1; i <= n; i++) {
cin >> a[i];
state[a[i]].pb(i);
}
}
int tt = 0;
int dep[mxN];
pii range[mxN];
int lift[mxN][20];
void dfs1(int u = 1, int par = 0, int depth = 1) {
dep[u] = depth;
range[u].ff = ++tt;
lift[u][0] = par;
for (int &v : adj[u]) {
if (v == par) continue;
dfs1(v, u, depth + 1);
}
range[u].ss = tt;
}
void BuildLift() {
for (int bit = 1; bit < 20; bit++) {
for (int i = 1; i <= n; i++) {
lift[i][bit] = lift[lift[i][bit - 1]][bit - 1];
}
}
}
int FindLCA(int u, int v) {
if (dep[u] > dep[v]) swap(u, v);
int diff = dep[v] - dep[u];
for (int i = 19; i >= 0; i--) {
if (diff & (1 << i)) {
v = lift[v][i];
}
}
if (u == v) return u;
for (int i = 19; i >= 0; i--) {
if (lift[u][i] != lift[v][i]) {
u = lift[u][i];
v = lift[v][i];
}
}
return lift[u][0];
}
bool cmp(int &x, int &y) {
return range[x].ff < range[y].ff;
}
int dp[mxN];
void dfs2(int u = 1, int par = 0) {
for (int &v : adj[u]) {
if (v == par) continue;
dfs2(v, u);
dp[u] += dp[v];
}
}
int dsupp[mxN];
int DSUFind(int u) {
if (dsupp[u] == 0) return u;
return (dsupp[u] = DSUFind(dsupp[u]));
}
void DSUMerge(int u, int v) {
u = DSUFind(u);
v = DSUFind(v);
if (u != v) dsupp[v] = u;
}
int deg[mxN];
void solve() {
Input();
dfs1();
BuildLift();
for (int i = 1; i <= k; i++) {
sort(state[i].begin(), state[i].end(), cmp);
for (int j = 1; j < (int)(state[i].size()); j++) {
int u = state[i][j - 1], v = state[i][j];
int lca = FindLCA(u, v);
// colour edges from u to lca and from v to lca
dp[u]++; dp[lca]--;
dp[v]++; dp[lca]--;
}
}
dfs2();
for (int i = 2; i <= n; i++) {
if (dp[i] > 0) {
DSUMerge(i, lift[i][0]);
}
}
// find degree of tree after merging
for (int i = 2; i <= n; i++) {
if (dp[i] == 0) {
deg[DSUFind(i)]++;
deg[DSUFind(lift[i][0])]++;
}
}
int leaves = 0;
for (int i = 1; i <= n; i++) {
leaves += (deg[i] == 1);
}
cout << (leaves + 1) / 2 << endl;
}
int32_t main() {
ios::sync_with_stdio(0); cin.tie(0);
solve();
}
