// She will give birth to a son, and you are to give him the name Jesus,
// because he will save his people from their sins.
// Matthew 1:21
#include <bits/stdc++.h>
using namespace std;
template <class T>
inline bool mnto(T& a, T b) {return a > b ? a = b, 1 : 0;}
template <class T>
inline bool mxto(T& a, T b) {return a < b ? a = b, 1: 0;}
#define REP(i, s, e) for (int i = s; i < e; i++)
#define RREP(i, s, e) for (int i = s; i >= e; i--)
typedef long long ll;
typedef long double ld;
#define MP make_pair
#define FI first
#define SE second
typedef pair<int, int> ii;
typedef pair<ll, ll> pll;
#define MT make_tuple
typedef tuple<int, int, int> iii;
#define ALL(_a) _a.begin(), _a.end()
#define pb push_back
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<ii> vii;
#ifdef DEBUG
#define debug(args...) printf(args)
#else
#define debug(args...)
#endif
#define INF 1000000005
#define LINF 1000000000000000005
#define MOD 1000000007
#define MAXN 500005
#define MAXL 20
int n, k;
vi adj[MAXN], nadj[MAXN];
int s[MAXN];
vi col[MAXN];
bool visited[MAXN];
int ans;
int pre[MAXN], pst[MAXN], l[MAXN], p[MAXL][MAXN], ptr;
void dfs(int u, int cp) {
pre[u] = ptr++;
p[0][u] = cp;
REP (k, 1, MAXL) {
if (p[k - 1][u] == -1) {
p[k][u] = -1;
} else {
p[k][u] = p[k - 1][p[k - 1][u]];
}
}
for (int v : adj[u]) {
if (v == cp) continue;
l[v] = l[u] + 1;
dfs(v, u);
}
pst[u] = ptr;
}
int lca(int a, int b) {
if (l[a] < l[b]) swap(a, b);
RREP (k, MAXL - 1, 0) {
if (p[k][a] == -1) continue;
if (l[p[k][a]] >= l[b]) {
a = p[k][a];
}
}
if (a == b) {
return a;
}
RREP (k, MAXL - 1, 0) {
if (p[k][a] != p[k][b]) {
a = p[k][a];
b = p[k][b];
}
}
return p[0][a];
}
int dsup[MAXN], rnk[MAXN], compp[MAXN];
int findp(int a) {
if (dsup[a] == a) return a;
return dsup[a] = findp(dsup[a]);
}
bool join(int a, int b) {
int pa = findp(a), pb = findp(b);
int np = compp[pb];
if (pa == pb) return 0;
if (rnk[pa] < rnk[pb]) swap(pa, pb);
if (rnk[pa] == rnk[pb]) rnk[pa]++;
dsup[pb] = pa;
compp[pa] = np;
return 1;
}
int main() {
int _t = 1;
//scanf("%d", &_t);
while (_t--) {
scanf("%d%d", &n, &k);
REP (i, 0, n + 1) {
dsup[i] = i;
}
REP (i, 1, n) {
int a, b; scanf("%d%d", &a, &b);
adj[a].pb(b);
adj[b].pb(a);
}
REP (i, 1, n + 1) {
scanf("%d", &s[i]);
col[s[i]].pb(i);
}
dfs(1, -1);
REP (i, 1, n + 1) {
compp[i] = p[0][i];
}
REP (i, 1, k + 1) {
if (col[i].size() == 1) continue;
sort(ALL(col[i]), [&] (int l, int r) {
return pre[l] < pre[r];
});
int lc = col[i][0];
for (int u : col[i]) {
lc = lca(lc, u);
}
for (int u : col[i]) {
while (compp[findp(u)] != -1 && l[compp[findp(u)]] >= l[lc]) {
join(u, compp[findp(u)]);
}
}
}
int sze = 0;
REP (u, 1, n + 1) {
debug("%d: %d\n", u, findp(u));
for (int v : adj[u]) {
if (findp(u) == findp(v)) {
continue;
}
nadj[findp(u)].pb(findp(v));
}
}
REP (u, 1, n + 1) {
if (visited[findp(u)]) continue;
visited[findp(u)] = 1;
sze++;
}
REP (i, 1, n + 1) {
if (nadj[i].empty()) continue;
sort(ALL(nadj[i]));
nadj[i].erase(unique(ALL(nadj[i])), nadj[i].end());
}
REP (i, 1, n + 1) {
if (nadj[i].size() == 1) {
ans++;
}
}
printf("%d\n", (ans + 1) / 2);
}
return 0;
}
