#include <bits/stdc++.h>
using namespace std;
#define mp make_pair
#define pb push_back
#define fi first
#define se second
const int N = 5e5 + 7;
int n, k, u, v, s[N], level[N], sub[N], par[20][N], cnt = 0, pset[N], ret[N], sz[N], ans = 0;
bool vis[N], col[N];
vector <int> edge[N], tp[N], g[N], leaf;
map < pair <int, int>, int > ed;
void predfs(int u, int p){
int ch = 0;
for(int v : edge[u]){
if(v == p) continue;
par[0][v] = u;
level[v] = level[u] + 1;
predfs(v, u);
ch++;
}
if(ch == 0) leaf.pb(u);
}
int lca(int u, int v){
if(level[u] > level[v]) swap(u, v);
for(int i = 19; i >= 0; i--) if(level[par[i][v]] >= level[u]) v = par[i][v];
for(int i = 19; i >= 0; i--) if(par[i][u] != par[i][v]) u = par[i][u], v = par[i][v];
if(u == v) return u;
return par[0][u];
}
int fset(int x){
if(pset[x] == x) return x;
return pset[x] = fset(pset[x]);
}
void unionset(int u, int v){
u = fset(u), v = fset(v);
if(u == v) return;
pset[u] = v;
sz[v] += sz[u];
sz[u] = 0;
}
void dfs(int u, int p){
int child = 0;
for(int v : g[u]){
if(v == p) continue;
child ++;
dfs(v, u);
}
if(child == 0 || (child == 1 && u == 1)) ans++;
}
int main(){
ios_base::sync_with_stdio(0);
cin >> n >> k;
for(int i = 1; i < n; i++){
cin >> u >> v;
edge[u].pb(v);
edge[v].pb(u);
}
for(int i = 1; i <= n; i++){
cin >> s[i];
tp[s[i]].pb(i);
}
par[0][1] = 1;
level[1] = 1;
predfs(1, 1);
for(int i = 1; i <= 19; i++){
for(int j = 1; j <= n; j++){
par[i][j] = par[i - 1][par[i - 1][j]];
}
}
for(int i = 1; i <= k; i++){
pset[i] = i;
sz[i] = 1;
if(tp[i].empty()) continue;
int cur = tp[i][0];
for(int j = 1; j < (int)tp[i].size(); j++){
cur = lca(cur, tp[i][j]);
}
sub[cur]++;
}
priority_queue < pair <int, int> > q;
for(int x : leaf) vis[x] = true, q.push(mp(level[x], x));
while(!q.empty()){
int u = q.top().se;
q.pop();
int p = fset(s[u]);
sz[p] -= sub[u];
if(!vis[par[0][u]]){
vis[par[0][u]] = true;
q.push(mp(level[par[0][u]], par[0][u]));
}
if(sz[fset(p)] == 0) continue;
unionset(p, s[par[0][u]]);
}
for(int i = 1; i <= k; i++){
if(pset[i] == i) ret[i] = ++cnt;
}
for(int i = 1; i <= k; i++){
if(pset[i] != i) ret[i] = ret[fset(i)];
}
for(int i = 1; i <= n; i++){
int id = ret[s[i]];
for(int j : edge[i]){
int jd = ret[s[j]];
if(id == jd) continue;
if(ed.count(mp(id, jd))) continue;
g[id].pb(jd);
g[jd].pb(id);
ed[mp(id, jd)]++;
ed[mp(jd, id)]++;
}
}
dfs(1, 1);
if(ans == 1) cout << 0;
else cout << (ans + 1) / 2;
}
