// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>
using namespace std;
#define nl '\n'
#define pb push_back
#define pf push_front
#define mp make_pair
#define f first
#define s second
#define sz(x) int(x.size())
template<class T> using V = vector<T>;
using pi = pair<int, int>;
using vi = V<int>;
using vpi = V<pi>;
using ll = long long;
using pl = pair<ll, ll>;
using vpl = V<pl>;
using vl = V<ll>;
using db = long double;
template<class T> using pq = priority_queue<T, V<T>, less<T>>;
const int MOD = 1e9 + 7;
const ll INFL = ll(1e17);
const int LG = 19;
int main() {
cin.tie(0)->sync_with_stdio(0);
int N, K; cin >> N >> K;
V<vi> adj(N); for(int i = 0; i < N - 1; i++) {
int u, v; cin >> u >> v; --u, --v;
adj[u].pb(v);
adj[v].pb(u);
}
vi A(N); for(auto& x : A) { cin >> x; --x; }
V<vi> up(N, vi(LG)); vi dep(N);
function<void(int, int)> gen = [&](int u, int p) {
up[u][0] = p; dep[u] = (u == p ? 0 : dep[p] + 1);
for(int i = 1; i < LG; i++) up[u][i] = up[up[u][i-1]][i-1];
for(auto& v : adj[u]) if (v != p) gen(v, u);
};
auto jmp = [&](int u, int d) {
for(int i = 0; i < LG; i++) if ((d >> i) & 1) u = up[u][i];
return u;
};
auto lca = [&](int a, int b) {
if (dep[a] < dep[b]) swap(a, b);
a = jmp(a, dep[a] - dep[b]);
if (a == b) return a;
for(int i = LG - 1; i >= 0; i--) {
if (up[a][i] != up[b][i]) a = up[a][i], b = up[b][i];
}
return up[a][0];
};
gen(0, 0);
vi L(K, -1); for(int u = 0; u < N; u++) {
if (L[A[u]] == -1) L[A[u]] = u;
else L[A[u]] = lca(L[A[u]], u);
}
int t = 0; vi U(N), st(N), en(N), VT;
function<void(int, int)> dfs = [&](int u, int p) {
U[u] = L[A[u]];
st[u] = t++;
for(auto& v : adj[u]) if (v != p) {
dfs(v, u);
U[u] = lca(U[u], U[v]);
}
en[u] = t - 1;
if (U[u] == u) VT.pb(u);
};
dfs(0, 0);
if (sz(VT) == 1) {
cout << 0 << nl;
exit(0-0);
}
sort(begin(VT), end(VT), [&](int u, int v) {
return st[u] < st[v];
});
vi stk = {-1}; V<vi> ADJ(N);
for(auto& u : VT) {
while(stk.back() != -1 && en[stk.back()] < st[u]) stk.pop_back();
if (stk.back() != -1) {
ADJ[stk.back()].pb(u);
ADJ[u].pb(stk.back());
}
stk.pb(u);
}
int leaves = 0;
for(auto& u : VT) if (size(ADJ[u]) == 1) leaves++;
cout << (leaves + 1) / 2 << nl;
exit(0-0);
}
