#include <bits/stdc++.h>
/*
An edge is separable if the states on either side are disjoint
"Unify" an entire path between edges
Every city is a unique state -> min number of paths to cover induced tree of separable edges
Root at "centroid" (vertex that splits leaves into sections of less than half), get leaves -> solved
STL and look at num. distinct values to see if separable
*/
std::vector<std::vector<int>> edges;
std::vector<int> states;
std::vector<int> stamounts;
std::vector<int> parents;
std::vector<int> separable;
int nleaves=0;
std::map<int,int>* dfs(int cur,int parent=0){
std::map<int,int>* merge=new std::map<int,int>;
(*merge)[states[cur]]++;
if(stamounts[states[cur]]==1){
merge->erase(states[cur]);
}
for(int i:edges[cur]){
if(i==parent)continue;
parents[i]=cur;
std::map<int,int>* newm=dfs(i,cur);
if(newm->size()>merge->size())std::swap(merge,newm);
for(std::pair<int,int> j:*newm){
(*merge)[j.first]+=j.second;
if((*merge)[j.first]==stamounts[j.first])merge->erase(j.first);
}
delete newm;
}
if(merge->empty()){
separable[cur]=1;
}
return merge;
}
int dfs2(int cur){
int nhsep=0;
for(int i:edges[cur]){
if(i==parents[cur])continue;
nhsep+=dfs2(i);
}
if(cur==0&&nhsep<=1){
nleaves++;//if root is a leaf
}else if(separable[cur]){
if(!nhsep)nleaves++;
nhsep=1;
}
return nhsep;
}
int main(){
std::ios::sync_with_stdio(0);
std::cin.tie(0);
int n,k;
std::cin>>n>>k;
edges.resize(n);
parents.resize(n);
stamounts.resize(k);
separable.resize(n);
for(int i=1;i<n;i++){
int a,b;
std::cin>>a>>b;
a--,b--;
edges[a].push_back(b);
edges[b].push_back(a);
}
for(int i=0;i<n;i++){
int x;
std::cin>>x;
x--;
states.push_back(x);
stamounts[x]++;
}
std::map<int,int>* res=dfs(0);
delete res;
dfs2(0);
std::cout<<(nleaves==1?0:(nleaves+1)/2)<<'\n';
}
