#include "bits/stdc++.h"
using namespace std;
const int MAXN = 5e5 + 10;
#define int long long
vector<int> adj[MAXN];
int fin[MAXN];
int s[MAXN];
int dsu[MAXN];
int set_of(int u) {
if(dsu[u] == u) return u;
return dsu[u] = set_of(dsu[u]);
}
void union_(int u, int v) {
dsu[set_of(u)] = set_of(v);
}
vector<int> e;
int dep[MAXN];
int tin[MAXN];
int tim = 0;
void dfs1(int node, int prev, int cur) {
e.push_back(node);
dep[node] = cur;
tin[node] = ++tim;
for(int x: adj[node]) {
if(x != prev) {
dfs1(x, node, cur + 1);
e.push_back(node);
}
}
}
pair<int, int> st[8*MAXN];
void u(int l, int r, int tar, int idx, int val, int o) {
if(l == r) {
st[idx] = {val, o};
return;
}
int mid = (l+r) >> 1;
if(tar <= mid) u(l, mid, tar, 2*idx+1, val, o);
else u(mid+1, r, tar, 2*idx+2, val, o);
st[idx] = min(st[2*idx+1], st[2*idx+2]);
}
pair<int, int> qu(int l, int r, int constl, int constr, int idx) {
if(l<=constl && constr<=r) return st[idx];
int mid = (constl + constr) >> 1;
if(mid < l || r < constl) return qu(l, r, mid+1, constr, 2*idx+2);
if(constr < l || r < mid+1) return qu(l, r, constl, mid, 2*idx+1);
return min(
qu(l, r, constl, mid, 2*idx+1),
qu(l, r, mid+1, constr, 2*idx+2)
);
}
void update(int i, int v, int key) {
u(0, 2*MAXN-1, i, 0, v, key);
}
int l[MAXN], r[MAXN];
int lca(int x, int y) {
int m1 = min(l[x], l[y]);
int m2 = max(r[x], r[y]);
return qu(m1, m2, 0, 2*MAXN-1, 0).second;
}
int delta[MAXN];
bool cmp(int a, int b) {
return tin[a] < tin[b];
}
map<pair<int, int>, bool> lit;
int dfs2(int node, int prev) {
int s = delta[node];
for(int x: adj[node]) {
if(x != prev) s += dfs2(x, node);
}
if(s == 0) lit[{node, prev}] = lit[{prev, node}] = 1;
return s;
}
int32_t main() {
ios::sync_with_stdio(0);
cin.tie(0);
int n,k;cin >> n >> k;
for(int i=1;i<n;i++) {
int a,b;cin >> a >> b;
adj[a].push_back(b);
adj[b].push_back(a);
}
for(int i=1; i<=n; i++) cin >> s[i];
for(int i=0; i<=n; i++) dsu[i] = i;
dfs1(1, -1, 0);
for(int i=0; i<e.size(); i++) r[e[i]] = i + 1;
for(int i=e.size()-1; i>=0; i--) l[e[i]] = i + 1;
for(int i=0; i<e.size(); i++) update(i + 1, dep[e[i]], e[i]);
vector<int> wow[k+1];
for(int i=1; i<=n; i++) {
wow[s[i]].push_back(i);
}
for(int i=1; i<=k; i++) {
if(wow[i].size() == 1) continue;
sort(wow[i].begin(), wow[i].end(), cmp);
int l = lca(wow[i][0], wow[i][wow[i].size() - 1]);
for(int j=0; j<wow[i].size(); j++) {
delta[wow[i][j]]++;
}
delta[l] -= wow[i].size();
}
dfs2(1, -1);
for(int i=1; i<=n; i++) {
for(int x: adj[i]) {
if(!lit[{i, x}]) {
union_(i, x);
}
}
}
lit.clear();
for(int i=1; i<=n; i++) {
for(int x: adj[i]) {
if(set_of(i) != set_of(x) && lit[{set_of(i), set_of(x)}] == 0) {
lit[{set_of(i), set_of(x)}] = 1;
lit[{set_of(x), set_of(i)}] = 1;
fin[set_of(i)]++;
fin[set_of(x)]++;
}
}
}
int s = 0;
for(int i=1; i<=n; i++) {
s += (fin[i] == 1);
}
cout << (s + 1) / 2 << "\n";
}
