#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 x, int y) {
x=get(x); y=get(y);
if(x == y) return false;
if(e[x] > e[y]) swap(x, y);
e[x]+=e[y]; e[y]=x;
return true;
}
};
vector<vector<int>> adj, parent;
vector<int> depth, timeIn;
int curTime=0;
void dfs1(int node, int prev, int dis) {
depth[node] = dis;
parent[node][0] = prev;
timeIn[node]=curTime++;
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];
}
int n;
vector<int> deg;
void dfs2(int node, int prev, DSU&dsu) {
for(auto child : adj[node]) if(child != prev) {
int u=dsu.get(child), v=dsu.get(node);
if(u != v) {
deg[u]++;
deg[v]++;
}
dfs2(child, node, dsu);
}
}
signed main() {
int 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);
}
parent = vector<vector<int>>(n+1, vector<int>(20, 0));
depth = vector<int>(n+1, 0); timeIn = vector<int>(n+1, 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];
}
}
vector<int> type(n);
vector<vector<int>> group(k+1);
vector<vector<pair<int, int>>> timings(k+1);
for(int i=0; i<n; i++) {
cin >> type[i];
group[type[i]].push_back(i+1);
timings[type[i]].push_back({timeIn[i+1], i+1});
}
DSU dsu(n+1);
for(int i=1; i<=k; i++) if(!group[i].empty()) {
sort(timings[i].begin(), timings[i].end());
for(int j=1; j<timings[i].size(); j++) {
int curLca = lca(timings[i][j].second, timings[i][j-1].second);
int cur = timings[i][j].second;
while(cur != curLca) {
dsu.unite(curLca, cur);
cur = parent[cur][0];
}
cur = timings[i][j-1].second;
while(cur != curLca) {
dsu.unite(curLca, cur);
cur = parent[cur][0];
}
}
}
deg = vector<int>(n+1, 0);
dfs2(1, 0, dsu);
int leaves=0;
for(auto x : deg) if(x == 1) leaves++;
cout << (leaves+1)/2;
return 0;
}
