#include <bits/stdc++.h>
using namespace std;
int n,k;
vector<int> adj[200005];
int arr[200005],tot[200005];
int sz[200005],del[200005];
int dfssize(int x, int p){
sz[x]=1;
for(int i:adj[x]){
if(i==p||del[i]) continue;
sz[x]+=dfssize(i,x);
}
return sz[x];
}
int findcent(int x, int p, int tsz){
for(int i:adj[x]){
if(i==p||del[i]) continue;
if(sz[i]*2>tsz) return findcent(i,x,tsz);
}
return x;
}
vector<int> grr[200005];
int par[200005],v[200005],vcol[200005];
int ans;
vector<int> undo;
void dfs(int x, int p){
grr[arr[x]].push_back(x);
undo.push_back(arr[x]);
par[x]=p;
v[x]=0;
vcol[arr[x]]=0;
for(int i:adj[x]){
if(i==p||del[i]) continue;
dfs(i,x);
}
}
void build(int x){
x=findcent(x,-1,dfssize(x,-1));
dfs(x,-1);
vector<int> q;
q.push_back(x);
bool can=true;
int col=0;
while(!q.empty()){
int yay=q.back();
q.pop_back();
if(vcol[arr[yay]]) continue;
vcol[arr[yay]]=1;
col++;
if((int)grr[arr[yay]].size()!=tot[arr[yay]]){
can=false;
break;
}
for(int i:grr[arr[yay]]){
int cur=i;
while(cur!=-1&&!v[cur]){
q.push_back(cur);
v[cur]=1;
cur=par[cur];
}
}
}
if(can){
ans=min(ans,col);
}
del[x]=1;
for(int i:undo) grr[i].clear();
undo.clear();
for(int i:adj[x]){
if(!del[i]) build(i);
}
}
int32_t main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> k;
for(int i=0; i<n-1; 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 >> arr[i];
tot[arr[i]]++;
}
ans=n;
build(1);
cout << ans-1;
}
