#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;
vector<int> A[500009], adj[500009];
int S[500009], in[500009], ou[500009], t, p[22][500009], np[500009], l;
int uf[500009], deg[500009];
inline bool isup(int u, int v) {return in[u] <= in[v] && ou[u] >= ou[v];}
int LCA(int u, int v) {
if(isup(u, v)) return u;
if(isup(v, u)) return v;
for(int i=l; i>=0; i--) if(!isup(p[i][u], v)) u = p[i][u];
return p[0][u];
}
void dfs(int x, int par) {
in[x] = ++t;
p[0][x] = np[x] = par;
for(auto& it: adj[x]) if(it != par) dfs(it, x);
ou[x] = ++t;
}
int root(int x) {
if(uf[x] == x) return x;
return uf[x] = root(uf[x]);
}
void merg(int u, int v) {
u = root(u); v = root(v);
uf[u] = v;
}
void mrg(int now, int anc) {
if(isup(now, anc)) return;
if(S[now] != S[np[now]]) merg(S[now], S[np[now]]);
mrg(np[now], anc);
np[now] = anc;
}
int main() {
int N, K; scanf("%d%d",&N,&K);
for(int i=1; i<=K; i++) uf[i] = i;
for(int i=0; i<N-1; i++) {
int u, v; scanf("%d%d",&u,&v);
adj[u].push_back(v);
adj[v].push_back(u);
}
dfs(1, 1);
for(int i=1; (1<<i)<=N; i++) {
for(int j=1; j<=N; j++) p[i][j] = p[i-1][p[i-1][j]];
l = i;
}
for(int i=1; i<=N; i++) {
scanf("%d",&S[i]);
A[S[i]].push_back(i);
}
vector<pii> Q;
for(int i=1; i<=K; i++) {
sort(A[i].begin(), A[i].end(), [&](int P, int Q) {return in[P] < in[Q];});
for(int j=1; j<A[i].size(); j++) {
int u = A[i][j-1], v = A[i][j];
int lca = LCA(u, v);
Q.push_back({u, lca});
Q.push_back({v, lca});
}
}
for(auto& it: Q) {
int now, anc; tie(now, anc) = it;
mrg(now, anc);
}
for(int i=1; i<=N; i++) {
for(auto& it: adj[i]) {
if(i < it) {
int u = root(S[i]), v = root(S[it]);
if(u != v) {
++deg[u];
++deg[v];
}
}
}
}
int cnt = 0;
for(int i=1; i<=K; i++) if(deg[i] == 1) ++cnt;
printf("%d", (cnt+1) / 2);
return 0;
}
