#include <bits/stdc++.h>
using namespace std;
const int maxn = 5e5 + 5;
int n, k;
int dp[20][maxn];
int where[maxn];
int tym = 0;
vector<int> g[maxn], state[maxn];
int s[maxn];
int lvl[maxn];
int p[maxn], sz[maxn];
using ii = pair<int, int>;
vector<ii> bridges;
int cnt[maxn];
int find(int u) {
return p[u] == u ? u : p[u] = find(p[u]);
}
void unite(int u, int v) {
u = find(u);
v = find(v);
if(u == v) return;
if(sz[u] > sz[v]) swap(u, v);
sz[v] += sz[u];
p[u] = v;
}
void dfs(int u, int par) {
for(int v : g[u]) if(v != par) {
dfs(v, u);
if(s[v]) unite(u, v);
else bridges.emplace_back(u, v);
s[u] += s[v];
}
}
void dfs0(int u, int par) {
lvl[u] = par + 1 ? lvl[par] + 1 : 0;
where[u] = ++ tym;
dp[0][u] = par;
for(int i = 1; i <= 19; i++) {
int mid = dp[i - 1][u];
if(mid != -1) dp[i][u] = dp[i - 1][mid];
}
for(int v : g[u]) if(v != par) {
dfs0(v, u);
}
}
int __lca(int u, int v) {
if(lvl[u] > lvl[v]) swap(u, v);
int d = lvl[v] - lvl[u];
for(int i = 19; i >= 0; i--) if(d >> i & 1) {
v = dp[i][v];
}
if(u == v) return u;
for(int i = 19; i >= 0; i--) {
if(dp[i][u] != dp[i][v]) {
u = dp[i][u];
v = dp[i][v];
}
}
return dp[0][u];
}
int main(int argc, char const *argv[])
{
// freopen("in", "r", stdin);
memset(dp, -1, sizeof dp);
cin >> n >> k;
for(int i = 1; i < n; i++) {
int u, v; cin >> u >> v;
g[u].emplace_back(v);
g[v].emplace_back(u);
}
for(int i = 1; i <= n; i++) {
int x; cin >> x;
state[x].emplace_back(i);
}
dfs0(1, -1);
for(int i = 1; i <= k; i++) {
sort(state[i].begin(), state[i].end(), [&](int x, int y){ return where[x] < where[y]; });
for(int j = 1; j < state[i].size(); j++) {
int u = state[i][j - 1], v = state[i][j];
s[u]++, s[v]++, ----s[__lca(u, v)];
}
}
for(int i = 1; i <= n; i++){
p[i] = i, sz[i] = 1;
}
dfs(1, -1);
vector<int> tmp;
for(ii e : bridges) {
int u = e.first;
int v = e.second;
u = find(u);
v = find(v);
cnt[u]++;
cnt[v]++;
tmp.emplace_back(u);
tmp.emplace_back(v);
}
sort(tmp.begin(), tmp.end());
tmp.erase(unique(tmp.begin(), tmp.end()), tmp.end());
int ans = 0;
for(int u : tmp) {
if(cnt[u] == 1) ans++;
}
ans = (ans + 1) / 2;
cout << ans << endl;
return 0;
}
