#include<bits/stdc++.h>
using namespace std;
const int N=500005;
long long p[N][20],val[N],dep[N],st[N],id;
vector<vector<int>>adj;
void pre_dfs(int v,int par){
p[v][0]=par;
st[v]=id++;
for(int i=1;i<20;i++)p[v][i]=p[p[v][i-1]][i-1];
for(auto&u:adj[v]){
if(u==par)continue;
dep[u]=dep[v]+1;
pre_dfs(u,v);
}
}
int P[N],sz[N];
int f(int x){
return (P[x]==x?x:P[x]=f(P[x]));
}
void join(int a, int b){
a=f(a),b=f(b);
if(a==b)return;
if(sz[a]<sz[b])swap(a, b);
P[b]=a;
sz[a]+=sz[b];
}
void dfs_up(int v,int par){
for(auto&u:adj[v]){
if(u==par)continue;
dfs_up(u,v);
val[v]+=val[u];
}
if(val[v])join(v,par);
}
int LCA(int u,int v){
if(u==v)return u;
if(dep[u]<dep[v])swap(u,v);
int k=dep[u]-dep[v];
for(int i=__lg(k+1);i>=0;i--){
if(k&(1<<i))u=p[u][i];
}
if(u==v)return u;
for(int i=__lg(dep[u]+1);i>=0;i--){
if(p[u][i]==p[v][i])continue;
u=p[u][i];
v=p[v][i];
}
return p[u][0];
}
int cnt(int v,int par){
int res=0;
for(auto&u:adj[v]){
if(u==par)continue;
res+=cnt(u,v);
}
return max(res,(val[v]==0?1:0));
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n,k;
cin>>n>>k;
adj.resize(n+1);
for(int i=1;i<n;i++){
int u,v;
cin>>u>>v;
adj[u].push_back(v);
adj[v].push_back(u);
}
pre_dfs(1,0);
vector<vector<int>>state(k+1);
for(int i=1;i<=n;i++){
int x;
cin>>x;
state[x].push_back(i);
}
for(int i=1;i<=k;i++){
sort(state[i].begin(),state[i].end(),[](int i,int j){
return st[i]<st[j];
});
int lca=LCA(state[i][0],state[i].back());
for(int j=0;j<state[i].size();j++){
int u=state[i][j];
val[u]++;val[lca]--;
}
}
iota(P,P+n+1,0);
fill(sz,sz+n+1,1);
dfs_up(1,0);
vector<vector<int>>adj2(n+1);
for(int i=1;i<=n;i++){
for(auto&u:adj[i]){
if(f(i)!=f(u))adj2[f(i)].push_back(f(u));
}
}
int res=0;
for(int i=1;i<=n;i++)res+=(adj2[i].size()==1);
cout<<(res+1)/2;
return 0;
}
