#include <bits/stdc++.h>
#define int long long
using namespace std;
int a,b;
vector <int> z[1000005];
int type[1000005];
int limit[1000005];
int cur[1000005];
int sta[1000005];
int fin[1000005];
int rev[1000005];
int tour;
int child[1000005];
int big[1000005];
int mark[1000005];
int bag1,bag2;
int max1=0;
void dfs(int i,int par){
tour++;
sta[i]=tour;
rev[tour]=i;
child[i]=1;
big[i]=-1;
for (auto p:z[i]){
if (p==par){
continue;
}
dfs(p,i);
child[i]+=child[p];
if (big[i]==-1 || child[big[i]]<child[p]){
big[i]=p;
}
}
fin[i]=tour;
}
void dfs1(int i,int par,bool keep){
for (auto p:z[i]){
if (p!=par && p!=big[i]){
dfs1(p,i,0);
mark[i]=max(mark[i],mark[p]);
}
}
if (big[i]!=-1){
dfs1(big[i],i,1);
mark[i]=max(mark[i],mark[big[i]]);
}
for (auto p:z[i]){
if (p==par){
continue;
}
if (p==big[i]){
continue;
}
for (int j=sta[p];j<=fin[p];j++){
int x=rev[j];
x=type[x];
if (cur[x]==0){
bag2++;
}
cur[x]++;
if (cur[x]==limit[x]){
bag2--;
bag1++;
}
}
}
int x=type[i];
if (cur[x]==0){
bag2++;
}
cur[x]++;
if (cur[x]==limit[x]){
bag2--;
bag1++;
}
if (bag1 && !bag2 && par!=0 && !mark[i] ){
max1++;
mark[i]=1;
}
// cout << i << " " << bag1 << " " << bag2 << "\n";
if (!keep){
for (int j=sta[i];j<=fin[i];j++){
x=rev[j];
x=type[x];
if (cur[x]==limit[x]){
bag2++;
bag1--;
}
cur[x]--;
if (cur[x]==0){
bag2--;
}
}
}
}
signed main()
{
// freopen("test.txt", "r", stdin);
// freopen("o2.out", "w", stdout);
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> a >> b;
for (int i=1;i<a;i++){
int x,y;
cin >> x >> y;
z[x].push_back(y);
z[y].push_back(x);
}
for (int i=1;i<=a;i++){
cin >> type[i];
limit[type[i]]++;
}
dfs(1,0);
dfs1(1,0,1);
cout << (max1+1)/2 << "\n";
return 0;
}
/*
cccacaca
*/
/*
freopen("test.txt", "r", stdin);
freopen("o2.out", "w", stdout);
*/
