#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
const int MAXN = 500000;
const int MXLOG = 19;
int in[MAXN+5];
int out[MAXN+5];
int svih[MAXN+5];
int kome[MAXN+5];
vector <int> graf[MAXN+5];
int par[MAXN+5][MXLOG+1];
int tjm;
int depth[MAXN+5];
void dfs_calc(int v, int p){
in[v] = ++tjm;
par[v][0] = p;
depth[v] = depth[p] + 1;
for(int j=1; j<=MXLOG; j++) par[v][j] = par[par[v][j-1]][j-1];
for(auto c : graf[v]) if(c != p) dfs_calc(c, v);
out[v] = tjm;
}
bool is_parent(int a, int b){
return (a == 0) || (in[a] <= in[b] && out[b] <= out[a]);
}
int lca(int a, int b){
if(is_parent(a, b)) return a;
for(int j=MXLOG; j>=0; j--) if(!is_parent(par[a][j], b)) a = par[a][j];
return par[a][0];
}
bool deli[MAXN+5];
int dfs_traverse(int v, int p){
int mnh = depth[svih[kome[v]]];
for(auto c : graf[v]) if(c != p) mnh = min(mnh, dfs_traverse(c, v));
if(mnh >= depth[v]) deli[v] = 1;
return mnh;
}
vector <int> dgraf[MAXN+5];
void dfs_final(int v, int p, int lst){
int sd = lst;
if(deli[v]){
if(lst){
dgraf[lst].push_back(v);
dgraf[v].push_back(lst);
}
sd = v;
}
for(auto c : graf[v]) if(c != p) dfs_final(c, v, sd);
}
int main(){
ios_base::sync_with_stdio(false), cin.tie(0);
cout.precision(10);
cout << fixed;
int n, k;
cin >> n >> k;
for(int i=1; i<n; i++){
int a, b;
cin >> a >> b;
graf[a].push_back(b);
graf[b].push_back(a);
}
dfs_calc(1, 0);
for(int i=1; i<=n; i++){
cin >> kome[i];
if(!svih[kome[i]]) svih[kome[i]] = i;
else svih[kome[i]] = lca(svih[kome[i]], i);
}
dfs_traverse(1, 0);
dfs_final(1, 0, 0);
int leaves = 0;
for(int i=1; i<=n; i++) leaves += (dgraf[i].size() == 1);
cout << (leaves+1)/2 << "\n";
return 0;
}
