#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define ll long long
#define pii pair<int, int>
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
template <typename T> inline T range(T l, T r) {
return uniform_int_distribution <T>(l, r)(rng);
}
const int N = 2e5 + 15;
const int inf = 2e9;
const int mod = 1e9 + 7;
int n, m, k, a[N];
vector <int> g[N];
bool used[N];
int total[N], cnt[N];
int cl, sz[N], now, ans = inf;
int curp[N];
int q[N], ql, qr;
vector <int> ord[N];
struct dsu {
int par[N];
int find(int v) {
if(v == par[v])
return v;
return par[v] = find(par[v]);
}
bool unio(int a, int b) {
a = find(a);
b = find(b);
if(a == b)
return false;
if(range(0, 1))
swap(a, b);
par[b] = a;
return true;
}
} st;
void dfs_sz(int v, int p) {
sz[v] = 1;
st.par[a[v]] = a[v];
ord[a[v]].clear();
for(int to : g[v])
if(to != p && !used[to]) {
curp[to] = v;
dfs_sz(to, v);
sz[v] += sz[to];
}
}
int centroid(int v, int p, int n) {
for(int to : g[v])
if(to != p && !used[to] && 2 * sz[to] > n)
return centroid(to, v, n);
return v;
}
void calc(int v, int p) {
ord[a[v]].pb(v);
for(int to : g[v])
if(to != p && !used[to])
calc(to, v);
}
void solve(int c) {
curp[c] = -1;
used[c] = true;
dfs_sz(c, c);
calc(c, c);
ql = 0, qr = -1;
for(int x : ord[a[c]])
q[++qr] = x;
int cur = 0, now = 0;
while(ql <= qr) {
int v = q[ql++];
cur += (int)ord[a[v]].size() - total[a[v]];
// if(c == 2)
// cout << ord[a[v]].size() << ' ' << total[a[v]] << endl;
if(curp[v] == -1)
continue;
if(st.unio(a[curp[v]], a[v])) {
++now;
for(int x : ord[a[curp[v]]])
q[++qr] = x;
}
}
if(cur == 0 && now < ans)
ans = now;
for(int to : g[c])
if(!used[to])
solve(centroid(to, c, sz[to]));
}
main() {
ios_base::sync_with_stdio(0); cout.tie(0); cin.tie(0);
cin >> n >> k;
for(int i = 1; i < n; ++i){
int u, v;
cin >> u >> v;
g[u].pb(v);
g[v].pb(u);
}
for(int i = 1; i <= n; ++i) {
cin >> a[i];
++total[a[i]];
}
dfs_sz(1, 1);
solve(centroid(1, 1, n));
cout << ans << endl;
return 0;
}
