#include <iostream>
#include <vector>
using namespace std;
const int maxn = 5e5 + 5;
int n, k, t = 0;
int l[maxn], r[maxn];
int ls[maxn], rs[maxn], s[maxn];
int l2[maxn], r2[maxn];
vector<int> g[maxn];
bool c[maxn];
void dfs_time(int u, int p = -1)
{
l[u] = t++;
for (int v : g[u]) if (v != p) dfs_time(v, u);
r[u] = t - 1;
}
void dfs_critical(int u, int p = -1)
{
l2[u] = min(l[u], ls[s[u]]);
r2[u] = max(r[u], rs[s[u]]);
for (int v : g[u]) if (v != p)
{
dfs_critical(v, u);
l2[u] = min(l2[u], l2[v]);
r2[u] = max(r2[u], r2[v]);
}
if (u && l[u] == l2[u] && r[u] == r2[u])
c[u] = true;
}
int cuts = 0;
bool dfs_cover(int u, int p = -1)
{
bool is_covered = false;
for (int v : g[u]) if (v != p) is_covered |= dfs_cover(v, u);
if (!is_covered && c[u])
{
cuts++;
return true;
}
return is_covered;
}
int dfs_cuts_root_can_reach(int u, int p = -1)
{
if (c[u]) return 1;
int sum = 0;
for (int v : g[u]) if (v != p) sum += dfs_cuts_root_can_reach(v, u);
return sum;
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(0);
cin >> n >> k;
for (int i = 0, a, b; i < n - 1; i++)
{
cin >> a >> b;
g[--a].push_back(--b);
g[b].push_back(a);
}
dfs_time(0);
for (int i = 0; i < k; i++) ls[i] = 1e9, rs[i] = -1e9;
for (int i = 0; i < n; i++)
{
cin >> s[i]; s[i]--;
ls[s[i]] = min(ls[s[i]], l[i]);
rs[s[i]] = max(rs[s[i]], r[i]);
}
dfs_critical(0);
dfs_cover(0);
int ans = (cuts + 1) / 2;
int cnt = dfs_cuts_root_can_reach(0);
if (cuts % 2 == 0 && cnt == 1) ans++; // musime to este spojit aj s korenom
cout << ans << "\n";
return 0;
}
