#include <bits/stdc++.h>
using namespace std;
int n,k,t,cnt=1,deg[500001],color[500001],ent[500001],out[500001],mn[500001],mx[500001],par[500001];
vector<int> segmn,segmx,graph[500001];
set<pair<int,int>> st;
void dfs(int curr , int p){
ent[curr] = cnt++;
for(auto i : graph[curr]){
if(i == p){
continue;
}
par[i] = curr;
dfs(i,curr);
}
out[curr] = cnt-1;
}
void dfs2(int curr , int p , int rt){
// cout << curr << " " << p << " " << rt << endl;
for(auto i : graph[curr]){
if(i == p){
continue;
}
if(st.count({curr,i})){
deg[rt] += 1 , deg[cnt+1] += 1;
dfs2(i,curr,++cnt);
}else{
dfs2(i,curr,rt);
}
}
}
int getmax(int a , int b , int curr , int l , int r){
if(b < l || a > r){
return 0;
}
if(a <= l && b >= r){
return segmx[curr];
}
int mid = (l+r)/2;
return max(getmax(a,b,2*curr,l,mid),getmax(a,b,2*curr+1,mid+1,r));
}
int getmin(int a , int b , int curr , int l , int r){
if(b < l || a > r){
return 1000000;
}
if(a <= l && b >= r){
return segmn[curr];
}
int mid = (l+r)/2;
return min(getmin(a,b,2*curr,l,mid),getmin(a,b,2*curr+1,mid+1,r));
}
void upd(int curr , int v1 , int v2){
while(curr){
segmn[curr] = min(segmn[curr],v1);
segmx[curr] = max(segmx[curr],v2);
curr /= 2;
}
}
int main(){
cin >> n >> k;
t = pow(2,ceil(log2(n)));
segmn.resize(2*t,1000000),segmx.resize(2*t,0);
for(int i = 0 ; i < n-1 ; i += 1){
int a,b;
cin >> a >> b;
graph[a].push_back(b),graph[b].push_back(a);
}
for(int i = 1 ; i <= k ; i += 1){
mn[i] = 1000000 , mx[i] = 0;
}
for(int i = 1 ; i <= n ; i += 1){
cin >> color[i];
}
dfs(1,1);
for(int i = 1 ; i <= n ; i += 1){
mn[color[i]] = min(mn[color[i]],ent[i]);
mx[color[i]] = max(mx[color[i]],ent[i]);
}
for(int i = 1 ; i <= n ; i += 1){
upd(ent[i]+t-1,mn[color[i]],mx[color[i]]);
}
for(int i = 2 ; i <= n ; i += 1){
if(getmin(ent[i],out[i],1,1,t) >= ent[i] && getmax(ent[i],out[i],1,1,t) <= out[i]){
st.insert({par[i],i});
}
}
cnt = 1;
dfs2(1,1,1);
int num = 0;
for(int i = 1 ; i <= cnt ; i += 1){
if(deg[i] == 1){
num += 1;
}
}
cout << (num+1)/2 << endl;
}
