#include<bits/stdc++.h>
using namespace std;
typedef long long int lld;
typedef pair<lld,lld> pii;
#define rep(i,a,b) for(int i=a;i<b;i++)
#define trav(a,v) for(auto a:v)
#define INF 1000000000000000000
int n,k;
vector<int> nei[1000000];
int state[1000000];
vector<int> states[1000000];
int dfs_num[1000000];
int dfs_low[1000000];
stack<int> s;
int parent[1000000];
int counter;
int SCC_count;
int SCC[1000000];
int deg[1000000];
bool visited[1000000];
int parent_tree[1000000];
void DFS(int node){
dfs_num[node]=counter;
dfs_low[node]=counter;
counter++;
s.push(node);
visited[node]=true;
trav(a,nei[node]){
if(dfs_num[a]==-1){
parent[a]=node;
DFS(a);
dfs_low[node]=min(dfs_low[node],dfs_low[a]);
}else{
if(parent[node]!=a && visited[a]){
dfs_low[node]=min(dfs_low[node],dfs_num[a]);
}
}
}
if(dfs_low[node]==dfs_num[node]){
while(true){
int u=s.top();
s.pop();
visited[u]=false;
SCC[u]=SCC_count;
dfs_num[u]=-1;
if(u==node){
SCC_count++;
return;
}
}
}
}
void DFS2(int node){
visited[node]=true;
trav(a,nei[node]){
if(!visited[a]){
parent_tree[a]=node;
DFS2(a);
}
}
}
class DSU{
int parent[1000000];
int size[1000000];
public:
void init(int K){
rep(i,0,K){
parent[i]=i;
size[i]=1;
}
}
int root(int node){
if(parent[node]==node)return node;
parent[node]=root(parent[node]);
return parent[node];
}
void merge(int a, int b){
a=root(a);
b=root(b);
if(a==b)return;
if(size[a]<size[b])swap(a,b);
size[a]+=size[b];
parent[b]=a;
}
};
int main(){
scanf("%d %d",&n,&k);
rep(i,0,n)visited[i]=false;
vector<pii> edges;
rep(i,0,n-1){
int x,y;
scanf("%d %d",&x,&y);
x--;y--;
nei[x].push_back(y);
nei[y].push_back(x);
edges.push_back(pii(x,y));
edges.push_back(pii(y,x));
}
DFS2(0);
rep(i,0,n){
scanf("%d",&state[i]);
state[i]--;
states[state[i]].push_back(i);
}
rep(i,0,k){
rep(j,0,states[i].size()-1){
pii new_edge=pii(states[i][j],states[i][j+1]);
if(parent_tree[new_edge.first]!=new_edge.second && parent_tree[new_edge.second]!=new_edge.first){
nei[states[i][j]].push_back(states[i][j+1]);
nei[states[i][j+1]].push_back(states[i][j]);
}
//edges.push_back(pii(states[i][j],states[i][j+1]));
}
}
/*bool important[edges.size()];
rep(i,0,edges.size())important[i]=true;
rep(i,0,edges.size()){
rep(j,0,n){
visited[j]=false;
nei[j].clear();
}
rep(j,0,edges.size()){
if(j!=i){
nei[edges[j].first].push_back(edges[j].second);
nei[edges[j].second].push_back(edges[j].first);
}
}
DFS2(0);
rep(j,0,n){
important[i]=important[i]&visited[j];
}
}*/
/*rep(i,0,n-1)cout<<important[i];
cout<<endl;*/
/*rep(i,0,edges.size()){
if(important[i]){
nei[edges[i].first].push_back(edges[i].second);
nei[edges[i].second].push_back(edges[i].first);
}
}
rep(i,0,n){
trav(a,nei[i])cout<<a<<" ";
cout<<endl;
}cout<<endl;*/
rep(i,0,n){
dfs_low[i]=-1;
dfs_num[i]=-1;
visited[i]=false;
}
counter=0;
SCC_count=0;
DFS(0);
//rep(i,0,n)cout<<SCC[i]<<endl;
/*rep(i,0,n){
visited[i]=false;
}*/
/*SCC_count=0;
rep(i,0,n){
if(!visited[i]){
DFS2(i);
while(!s.empty()){
SCC[s.top()]=SCC_count;
s.pop();
}
SCC_count++;
}
}*/
//rep(i,0,n)cout<<SCC[i]<<endl;
DSU *D=new DSU();
D->init(SCC_count);
rep(i,0,k){
rep(j,0,states[i].size()-1){
pii new_edge=pii(states[i][j],states[i][j+1]);
if(!(parent_tree[new_edge.first]!=new_edge.second && parent_tree[new_edge.second]!=new_edge.first)){
D->merge(SCC[new_edge.first],SCC[new_edge.second]);
}
//edges.push_back(pii(states[i][j],states[i][j+1]));
}
}
rep(i,0,n)deg[i]=0;
trav(a,edges){
a.first=D->root(SCC[a.first]);
a.second=D->root(SCC[a.second]);
if(a.first!=a.second){
//cout<<a.first<<" "<<a.second<<endl;
deg[a.first]++;
deg[a.second]++;
}
}
int leaves=0;
rep(i,0,SCC_count){
if(deg[i]==2)leaves++;
}
printf("%d\n",(leaves+1)/2);
return 0;
}
