#include <bits/stdc++.h>
using namespace std;
#define int long long
#define form2(i, a, b) for (int i = (a); i < (b); ++i)
#define ford2(i, a, b) for (int i = (a-1); i >= b; --i)
#define form(i, n) form2(i, 0, n)
#define ford(i, n) ford2(i, n, 0)
#define chmax(x, v) x = max(x, (v))
#define chmin(x, v) x = min(x, (v))
#define fi first
#define se second
const long long BIG = 1000000000000000000LL;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
void cpr(string s, vector<int> v)
{ int i = 0; for (char c : s) { if (c == '$') cout << v[i++]; else cout << c; } cout << '\n'; }
void cpr(string s) { cpr(s, {}); }
void solve();
signed main()
{
ios::sync_with_stdio(false);
cin.tie(0);
solve();
return 0;
}
const int borne = 505*1000;
int drepr[borne];
int dfind(int x)
{
if (drepr[x] == x) return x;
else return drepr[x] = dfind(drepr[x]);
}
void dunir(int a, int b) // merge a dans b, b est le parent
{
a = dfind(a); b = dfind(b);
if (a == b) return;
drepr[a] = b;
}
// ww
int nbNoeuds, nbEtats;
int par[borne], prof[borne];
vector<int> adj[borne];
int gpOfNod[borne];
int deg[borne];
vector<int> nodInGp[borne];
void combiner(int a, int b)
{
a = dfind(a); b = dfind(b);
while (a != b) {
if (prof[a] < prof[b]) swap(a,b);
dunir(a, par[a]);
a = dfind(a);
}
}
void dfsInit(int nod)
{
for (int vo : adj[nod]) if (vo != par[nod]) {
par[vo] = nod;
prof[vo] = prof[nod] + 1;
dfsInit(vo);
}
}
void solve()
{
form(i, borne) { drepr[i] = i; par[i] = -1; }
cin >> nbNoeuds >> nbEtats;
form(i, nbNoeuds-1) {
int u, v;
cin >> u >> v;
--u; --v;
adj[u].push_back(v);
adj[v].push_back(u);
}
prof[0] = 0;
dfsInit(0);
form(nod, nbNoeuds) {
cin >> gpOfNod[nod]; --gpOfNod[nod];
nodInGp[gpOfNod[nod]].push_back(nod);
}
form(grp, nbEtats) {
int sz = nodInGp[grp].size();
form2(i, 1, sz) {
combiner(nodInGp[grp][0], nodInGp[grp][i]);
}
}
form(nod, nbNoeuds) {
for (int vo : adj[nod]) {
if (dfind(nod) != dfind(vo)) ++deg[dfind(nod)];
}
}
int lf = 0;
form(nod, nbNoeuds) if (dfind(nod) == nod && deg[nod] == 1) ++lf;
cout << (lf+1)/2 << "\n";
}
