#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 tree<long long, null_type, less<long long>, rb_tree_tag,
tree_order_statistics_node_update>
ordered_set;
typedef tree<long long, null_type, less_equal<long long>, rb_tree_tag,
tree_order_statistics_node_update>
ordered_multiset;
#define ll long long
#define iloop(m, h) for (auto i = m; i != h; i += (m < h ? 1 : -1))
#define jloop(m, h) for (auto j = m; j != h; j += (m < h ? 1 : -1))
#define kloop(m, h) for (auto k = m; k != h; k += (m < h ? 1 : -1))
#define lloop(m, h) for (auto l = m; l != h; l += (m < h ? 1 : -1))
#define pll pair<ll, ll>
#define INF 1000000000000000
#define MOD1 1000000007
#define MOD2 998244353
#define MOD3 1000000009
ll n, m, t1, t2, ans = 0;
vector<ll> adj[500005], b[500005];
ll twok[20][500005], dpt[500005], a[500005];
void dfs(ll nd, ll pr, ll dp) {
twok[0][nd] = pr;
dpt[nd] = dp;
iloop(1, 20) {
if (twok[i-1][nd] == -1) break;
twok[i][nd] = twok[i-1][twok[i-1][nd]];
}
for (auto it : adj[nd]) if (it != pr) dfs(it, nd, dp+1);
}
ll lca(ll x, ll y) {
if (dpt[x] < dpt[y]) swap(x, y);
iloop(19, -1) if (dpt[x] - dpt[y] >= 1<<i) x = twok[i][x];
if (x == y) return x;
iloop(19, -1) if (twok[i][x] != twok[i][y]) x = twok[i][x], y = twok[i][y];
return twok[0][x];
}
pair<ll, bool> dfs2(ll nd, ll pr) {
pair<ll, bool> res = {a[nd], 0}, tm;
for (auto it : adj[nd]) if (it != pr) {
tm = dfs2(it, nd);
res.first += tm.first, res.second |= tm.second;
}
if (res.first == 0 && !res.second && pr != -1) {
ans++;
res.second = 1;
}
return res;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> m;
iloop(1, n) {
cin >> t1 >> t2;
t1--, t2--;
adj[t1].push_back(t2);
adj[t2].push_back(t1);
}
iloop(0, n) {
cin >> t1;
t1--;
b[t1].push_back(i);
}
dfs(0, -1, 0);
ll cn;
iloop(0, m) {
cn = b[i][0];
for (auto it : b[i]) a[it]++, cn = lca(cn, it);
a[cn] -= b[i].size();
}
dfs2(0, -1);
cout << (ans+1)/2;
}
