#include <bits/stdc++.h>
using namespace std;
int main()
{
cin.tie(nullptr)->sync_with_stdio(0);
int n, k;
cin >> n >> k;
vector<int> m(n + 1);
vector<vector<int>> gg(k + 1), g(n + 1);
for(int i = 1; i < n; i++) {
int a, b;
cin >> a >> b;
g[a].push_back(b);
g[b].push_back(a);
}
for(int i = 1; i <= n; i++) {
cin >> m[i];
gg[m[i]].push_back(i);
}
vector<int> sub(n + 1), par(n + 1), cnt(k + 1);
vector<bool> used(n + 1), onq(k + 1);
function<int(int, int, int)> subsz = [&](int u, int p, int c) {
sub[u] = 1;
par[u] = p;
cnt[m[u]] += c;
onq[m[u]] = 0;
for(int to : g[u]) {
if(to == p || used[to]) {
continue;
}
sub[u] += subsz(to, u, c);
}
return sub[u];
};
function<int(int, int, int)> getcen = [&](int u, int p, int d) {
for(int to : g[u]) {
if(to == p || used[to]) {
continue;
}
if(sub[to] > d / 2) {
return getcen(to, u, d);
}
}
return u;
};
int ans = n;
function<void(int)> rek = [&](int u) {
subsz(u, u, 0);
u = getcen(u, u, sub[u]);
subsz(u, u, 1);
int use = 0;
queue<int> q;
onq[m[u]] = 1;
q.push(m[u]);
while(!q.empty()) {
int v = q.front();
q.pop();
if(cnt[v] != (int)gg[v].size()) {
use = n;
break;
}
for(int to : gg[v]) {
int look = m[par[to]];
if(onq[look] == 0) {
q.push(look);
onq[look] = 1;
use++;
}
}
}
ans = min(ans, use);
subsz(u, u, -1);
used[u] = true;
for(int to : g[u]) {
if(used[to]) {
continue;
}
rek(to);
}
};
rek(1);
cout << ans << '\n';
}
