#include <bits/stdc++.h>
using namespace std;
//#pragma GCC optimize ("O3")
//#pragma GCC target ("sse4")
#define endl "\n"
typedef long long ll;
template<class T, class T2> inline ostream &operator <<(ostream &out, const pair<T, T2> &x) { out << x.first << " " << x.second; return out;}
template<class T, class T2> inline istream &operator >>(istream &in, pair<T, T2> &x) { in >> x.first >> x.second; return in;}
template<class T, class T2> inline bool chkmax(T &x, const T2 &y) { return x < y ? x = y, 1 : 0; }
template<class T, class T2> inline bool chkmin(T &x, const T2 &y) { return x > y ? x = y, 1 : 0; }
const ll mod = 1e9 + 7;
#define out(x) "{" << (#x) << ": " << x << "} "
const int MAX_N = 1e5 + 10;
vector<int> g[MAX_N], nw[MAX_N];
int cnt[MAX_N], cntNow[MAX_N], col[MAX_N];
int n, k, ret;
int sz[MAX_N], big[MAX_N];
int cntok;
void add(int x, int p, int delta = 1) {
if(cntNow[col[x]] == 0 || cntNow[col[x]] == cnt[col[x]]) {
cntok --;
}
cntNow[col[x]] += delta;
if(cntNow[col[x]] == 0 || cntNow[col[x]] == cnt[col[x]]) {
cntok ++;
}
for(auto it : g[x]) {
if(it == p) {continue;}
add(it, x, delta);
}
}
void calcSize(int x, int p) {
sz[x] = 1;
big[x] = 0;
for(auto it : g[x]) {
if(it == p) {continue;}
calcSize(it, x);
sz[x] += sz[it];
if(sz[it] > sz[big[x]]) {
big[x] = it;
}
}
}
vector<int> dfs(int x, int p, bool keep = false) {
vector<int> ret;
for(auto it : g[x]) {
if(it == p || it == big[x]) {continue;}
auto curr = dfs(it, x, false);
for(auto it2 : curr) {
ret.push_back(it2);
}
}
if(big[x] != 0) {
auto curr = dfs(big[x], x, true);
for(auto it2 : curr) {
ret.push_back(it2);
}
}
for(auto it : g[x]) {
if(it == p || it == big[x]) {continue;}
add(it, x, 1);
}
if(cntNow[col[x]] == 0 || cntNow[col[x]] == cnt[col[x]]) {
cntok --;
}
cntNow[col[x]] ++;
if(cntNow[col[x]] == 0 || cntNow[col[x]] == cnt[col[x]]) {
cntok ++;
}
if(cntok == k) {
for(auto it : ret) {
nw[x].push_back(it);
}
ret = {x};
}
if(!keep) {
add(x, p, -1);
}
return ret;
}
void calc(int x, int d) {
if(x == 1 && nw[x].size() == 1) {
ret ++;
} else if(nw[x].size() == 0) {
ret ++;
}
for(auto it : nw[x]) {
calc(it, d + 1);
}
}
signed main() {
ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
cin >> n >> k;
cntok = k;
for(int i = 0; i < n - 1; 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 >> col[i];
cnt[col[i]] ++;
}
dfs(1, 0, 1);
calc(1, 0);
if(ret != 1) {
cout << (ret + 1) / 2 << endl;
} else {
cout << 0 << endl;
}
return 0;
}
