#pragma GCC optimize("O3,Ofast,unroll-loops,fast-math")
//#pragma GCC optimize("O3,Ofast")
#include <bits/stdc++.h>
#define int long long
using namespace std;
const int maxn = 5e5 + 100;
const int lg = 20;
int up[maxn][lg] , dep[maxn] , color[maxn];
vector<int> g[maxn];
vector<int> c[maxn];
vector<int> sholud_add[maxn];
void dfs(int u , int p){
up[u][0] = p;
for(int i = 1 ; i < lg ; i++)
up[u][i] = up[up[u][i - 1]][i - 1];
for(int &v : g[u]){
if(v == p)continue;
dep[v] = dep[u] + 1;
dfs(v, u);
}
}
int lca(int u , int v){
if(dep[u] < dep[v])swap(u , v);
for(int i = lg - 1 ; i >= 0 ; i--){
if(dep[u] - (1 << i) >= dep[v])
u = up[u][i];
}
if(u == v)return u;
for(int i = lg - 1 ; i >= 0 ; i--){
if(up[u][i] != up[v][i]){
v = up[v][i];
u = up[u][i];
}
}
return up[u][0];
}
int32_t main(){
int n , k; cin >> n >> k;
for(int i = 1 ; i < n ; i++){
int u , v;cin >> u >> v;
g[u].push_back(v);
g[v].push_back(u);
}
for(int i = 1 ; i <= n ; i++){
cin >> color[i];
c[color[i]].push_back(i);
}
dfs(1 , 0);
for(int i = 1 ; i <= k ; i++){
if(c[i].empty())continue;
int lc = c[i][0];
for(int &p : c[i])lc = lca(lc , p);
for(int &p : c[i])sholud_add[lc].push_back(p);
}
queue<int> prc;
vector<bool> marked(n + 1);
prc.push(1);
marked[1] = 1;
while(!prc.empty()){
int u = prc.front();prc.pop();
for(int v : sholud_add[u]){
if(marked[v])continue;
marked[v] = 1;
prc.push(v);
}
u = up[u][0];
while(marked[u] == 0 && u != 0){
prc.push(u);
marked[u] = 1;
u = up[u][0];
}
}
int ans = 1;
for(int i = 2 ; i <= n ; i++){
if(marked[up[i][0]] && !marked[i])ans++;
}
cout << (ans) / 2;
}
