#include<bits/stdc++.h>
using namespace std;
//#define int long long
const int MAX_SOM=500*1000+5,MAX_LOG=20;
int nbSom,nbGroupe,deb,fin,nbCompo,rep;
vector<int> adja[MAX_SOM];
int nbOccu[MAX_SOM],numGroupe[MAX_SOM],pere[MAX_SOM][MAX_LOG],numCompo[MAX_SOM];
int nbVois[MAX_SOM];
int lcaGroupe[MAX_SOM];
int prof[MAX_SOM];
int cumu[MAX_SOM];
vector<pair<int,int>> listeAre;
void marque(int pos,int idCompo) {
numCompo[pos]=idCompo;
for (int i:adja[pos]) {
if (i!=pere[pos][0] and numCompo[i]==0) {
marque(i,idCompo);
}
}
}
void DFS(int pos,int anci) {
pere[pos][0]=anci;
prof[pos]=prof[pere[pos][0]]+1;
for (int i:adja[pos]) {
if (i!=pere[pos][0]) {
DFS(i,pos);
}
}
}
int calcLca(int som1,int som2) {
if (prof[som1]>prof[som2]) {
swap(som1,som2);
}
for (int i=MAX_LOG-1;i>=0;i--) {
if (prof[pere[som2][i]]>=prof[som1]) {
som2=pere[som2][i];
}
}
if (som1==som2) {
return som1;
}
for (int i=MAX_LOG-1;i>=0;i--) {
if (pere[som1][i]!=pere[som2][i]) {
som1=pere[som1][i];
som2=pere[som2][i];
}
}
return pere[som1][0];
}
void DFS2(int pos) {
for (int i:adja[pos]) {
if (i!=pere[pos][0]) {
DFS2(i);
cumu[pos]+=cumu[i];
}
}
if (cumu[pos]==0) {
nbCompo++;
marque(pos,nbCompo);
}
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
cin>>nbSom>>nbGroupe;
for (int i=1;i<nbSom;i++) {
cin>>deb>>fin;
adja[deb].push_back(fin);
adja[fin].push_back(deb);
listeAre.push_back({deb,fin});
}
DFS(1,0);
for (int j=1;j<MAX_LOG;j++) {
for (int i=1;i<=nbSom;i++) {
pere[i][j]=pere[pere[i][j-1]][j-1];
}
}
for (int i=1;i<=nbSom;i++) {
cin>>numGroupe[i];
numGroupe[i]--;
nbOccu[numGroupe[i]]++;
if (nbOccu[numGroupe[i]]==1) {
lcaGroupe[numGroupe[i]]=i;
}
else {
lcaGroupe[numGroupe[i]]=calcLca(lcaGroupe[numGroupe[i]],i);
}
}
for (int i=1;i<=nbSom;i++) {
cumu[i]++;
cumu[lcaGroupe[numGroupe[i]]]--;
}
DFS2(1);
for (auto j:listeAre) {
deb=j.first;
fin=j.second;
if (numCompo[deb]!=numCompo[fin]) {
nbVois[numCompo[deb]]++;
nbVois[numCompo[fin]]++;
}
}
/*cout<<nbCompo<<endl;
for (int i=1;i<=nbSom;i++) {
cout<<i<<" : "<<numCompo[i]<<endl;
}*/
for (int i=1;i<=nbCompo;i++) {
if (nbVois[i]==1) {
rep++;
}
}
if (rep==1) {
cout<<0<<endl;
}
else {
cout<<(rep+1)/2<<endl;
}
return 0;
}
