// Starcraft 2 enjoyer //
#include <bits/stdc++.h>
// #pragma GCC target("avx2")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
using namespace std;
#define LSOne(X) ((X) & -(X))
const int N = 5e5 + 5;
const int M = 1 << 5;
const int K = 19;
const int LG = 20;
const long long INF = 3e18;
const int C = 26;
const int B = 1000;
const int MOD = 1e9 + 7;
int n, k, sz[N], p[N], par[N], st[N], en[N], cid, num, tot[N];
vector<int> adj[N], state[N], thing[N];
bool gud[N];
void dfs1(int c, int p)
{
sz[c] = 1;
par[c] = p;
st[c] = cid++;
for (int i : adj[c])
{
if (i == p)
continue;
dfs1(i, c);
sz[c] += sz[i];
}
en[c] = cid - 1;
}
void dfs2(int c, int p)
{
for (int i : adj[c])
{
if (i == p)
continue;
dfs2(i, c);
gud[c] |= gud[i];
tot[c] += tot[i];
}
for (int i : thing[c])
tot[c] += state[i].size();
if (!gud[c] && c != 1)
{
if (tot[c] == sz[c])
{
num++;
gud[c] = 1;
}
}
}
bool in(int a, int b)
{
return st[a] <= st[b] && en[b] <= en[a];
}
int parent(int i)
{
return p[i] == i ? i : parent(p[i]);
}
inline void solve()
{
cin >> n >> k;
for (int x = 0; x < n - 1; x++)
{
int a, b;
cin >> a >> b;
adj[a].push_back(b);
adj[b].push_back(a);
}
for (int x = 1; x <= n; x++)
{
int i;
cin >> i;
state[i].push_back(x);
p[x] = x;
}
cid = 1;
dfs1(1, 0);
for (int x = 1; x <= k; x++)
{
for (int y = 0; y < state[x].size() - 1; y++)
{
int i = state[x][y], j = state[x][y + 1];
while (!in(i, j))
{
int k = parent(par[i]);
p[i] = k;
i = k;
}
while (!in(j, i))
{
int k = parent(par[j]);
p[j] = k;
j = k;
}
}
thing[parent(state[x].back())].push_back(x);
}
num = 0;
dfs2(1, 0);
cout << (num + 1) / 2 << "\n";
}
signed main()
{
// freopen("CP.INP", "r", stdin);
// freopen("CP.OUT", "w", stdout);
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t = 1;
// cin >> t;
for (int x = 1; x <= t; x++)
{
solve();
}
return 0;
}
