#include<bits/stdc++.h>
using namespace std;
struct DSU {
vector<int> e;
DSU(int N) {e = vector<int>(N, -1);}
int get(int x) {return e[x] < 0 ? x : e[x]=get(e[x]);}
int size(int x) {return -e[get(x)];}
bool unite(int a, int b) {
a=get(a); b=get(b);
if(a == b) return false;
if(e[a] > e[b]) swap(a, b);
e[a]+=e[b]; e[b]=a;
return true;
}
};
int timer=0;
vector<int> depth, timeIn;
vector<vector<int>> adj, parent;
void dfs1(int node, int prev, int dis) {
timeIn[node]=timer++;
depth[node]=dis;
parent[node][0]=prev;
for(auto child : adj[node]) if(child != prev) dfs1(child, node, dis+1);
}
int ancestor(int x, int k) {
int cnt=0;
while(k&&x) {
if(k&1) x = parent[x][cnt];
k=k>>1; cnt++;
}
return x;
}
int lca(int a, int b) {
if(depth[a] < depth[b])swap(a, b);
a=ancestor(a, depth[a]-depth[b]);
if(a==b) return a;
for(int k=19; k>=0; k--) {
int aa=parent[a][k];
int bb=parent[b][k];
if(aa!=bb) {
a=aa; b=bb;
}
}
return parent[a][0];
}
vector<int> connections;
void dfs2(int node, int prev, DSU&dsu) {
for(auto child : adj[node]) if(prev != child) {
int u=dsu.get(node), v=dsu.get(child);
if(u != v) {
connections[u]++;
connections[v]++;
}
dfs2(child, node, dsu);
}
}
signed main() {
int n, k; cin >> n >> k;
adj = vector<vector<int>>(n+1);
for(int i=1; i<n; i++) {
int a, b; cin >> a >> b;
adj[a].push_back(b);
adj[b].push_back(a);
}
DSU dsu(n+1);
vector<int> type(n+1);
vector<vector<pair<int, int>>> groups(k+1);
timeIn = vector<int>(n+1);
depth = vector<int>(n+1);
parent = vector<vector<int>>(n+1, vector<int>(20, 0));
dfs1(1, 0, 0);
for(int k=1; k<20; k++) {
for(int i=1; i<=n; i++) {
if(parent[i][k-1]) parent[i][k] = parent[parent[i][k-1]][k-1];
}
}
for(int i=1; i<=n; i++) {
cin >> type[i];
groups[type[i]].push_back({timeIn[i], i});
}
for(int i=1; i<=k; i++) {
sort(groups[i].begin(), groups[i].end());
for(int j=1; j<groups[i].size(); j++) {
int curLca = lca(groups[i][j-1].second, groups[i][j].second);
int cur=groups[i][j-1].second;
while(cur != curLca) {
dsu.unite(curLca, cur);
cur=parent[cur][0];
}
cur=groups[i][j].second;
while(cur != curLca) {
dsu.unite(curLca, cur);
cur=parent[cur][0];
}
}
}
connections=vector<int>(n+1, 0);
dfs2(1, 0, dsu);
int tt=0;
for(auto x : connections) if(x == 1) tt++;
cout << (tt+1)/2;
return 0;
}
