#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
const int MAXN = 500007;
int N, K, rt = 1, ans = 0;
int dsu[MAXN], group[MAXN], last[MAXN], val[MAXN];
vector<int> adj[MAXN], add[MAXN];
int root(int u) { return (dsu[u] != u ? dsu[u] = root(dsu[u]) : u); }
void dfs(int u, int p)
{
dsu[u] = u;
for (int v : add[u]) {
if (dsu[v]) val[root(v)] -= 2;
}
for (int v : adj[u]) if (v != p) {
dfs(v, u);
dsu[v] = u;
val[u] += val[v];
}
if (u != rt && !val[u]) ++val[u], ++ans;
}
int main()
{
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> N >> K;
for (int i = 0; i < N - 1; ++i) {
int u, v;
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
for (int u = 1; u <= N; ++u) {
cin >> group[u];
if (last[group[u]]) {
int v = last[group[u]];
add[u].push_back(v);
add[v].push_back(u);
++val[u], ++val[v];
}
last[group[u]] = u;
}
if (N == 2) return cout << K - 1 << endl, 0;
for (rt = 1; adj[rt].size() == 1; ++rt);
dfs(rt, 0);
cout << (ans + 1) / 2 << endl;
return 0;
}
