#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
#define pb push_back
#define pii pair<int, int>
#define pll pair<ll, ll>
#define st first
#define nd second
#define ordered_set tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
#define debug false
#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
#define pb push_back
#define pii pair<int, int>
#define pll pair<ll, ll>
#define st first
#define nd second
#define ordered_set tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
#define debug false
const int MAXN = 500 * 1000 + 17;
const int MAXLOG = 22;
vector<int> graf[MAXN];
vector<int> vec[MAXN];
int ojc[MAXN];
int roz[MAXN];
int lca[MAXN];
int lev[MAXN];
int pam[MAXN][MAXLOG];
int deg[MAXN];
set<pii> s;
void DFS (int v, int p) {
pam[v][0] = p;
for (int i = 1; i < MAXLOG; i ++) {
pam[v][i] = pam[pam[v][i - 1]][i - 1];
}
for (auto x : graf[v]) {
if (x != p) {
lev[x] = lev[v] + 1;
DFS (x, v);
}
}
}
int LCA(int a, int b) {
if (lev[a] < lev[b]) {
swap(a, b);
}
int pot = (1 << (MAXLOG - 1));
for (int i = MAXLOG - 1; i >= 0; i--) {
if (lev[a] - pot >= lev[b]) {
a = pam[a][i];
}
pot /= 2;
}
if (a == b) {
return a;
}
for (int i = MAXLOG - 1; i >= 0; i--) {
if (pam[a][i] != pam[b][i]) {
a = pam[a][i];
b = pam[b][i];
}
}
return pam[a][0];
}
int findd(int x) {
if (ojc[x] != x){
ojc[x] = findd(ojc[x]);
}
return ojc[x];
}
void unionn(int x, int y) {
x = findd(x);
y = findd(y);
if (x == y) {
return;
}
if (roz[x] > roz[y]) {
swap(x, y);
}
roz[y] += roz[x];
ojc[x] = y;
lca[y] = LCA(lca[x], lca[y]);
}
int main() {
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int n, k;
cin >> n >> k;
int a, b;
for (int i = 0; i < n - 1; i ++) {
cin >> a >> b;
graf[a].pb(b);
graf[b].pb(a);
}
int x;
for (int i = 1; i <= n; i ++) {
cin >> x;
vec[x].pb(i);
}
for (int i = 1; i <= n; i++) {
ojc[i] = i;
roz[i] = 1;
lca[i] = i;
}
for (int i = 1; i <= k; i ++) {
for (auto x : vec[i]) {
unionn(x, vec[i][0]);
}
}
DFS(1, 1);
for (int i = 1; i <= k; i ++) {
for (auto x : vec[i]) {
s.insert({lev[lca[findd(x)]], lca[findd(x)]});
}
while (int(s.size()) > 1) {
pii el = *s.rbegin();
s.erase(el);
int o = pam[el.st][0];
unionn(el.st, o);
if (o != 1) {
s.insert({lev[lca[findd(o)]], lca[findd(o)]});
}
}
}
for (int i = 1; i <= n; i ++) {
//cout << findd(i) << "\n";
for (auto x : graf[i]) {
if (findd(i) != findd(x)) {
deg[findd(i)] ++;
}
}
}
int wyn = 0;
for (int i = 1; i <= n; i ++) {
//cout << deg[i] << "\n";
wyn += (deg[i] == 1);
}
cout << (wyn + 1)/2 << "\n";
return 0;
}
