#include<bits/stdc++.h>
#define fi first
#define se second
#define FOR(i, k, n) for(int i = k; i <= n; i++)
#define FOR1(i, k, n) for(int i = k; i >= n; i--)
#define pb push_back
#define fastio ios::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define vi vector<int>
#define pii pair<int, int>
#define vii vector<pii>
#define ll long long
#define vll vector<ll>
#define pll pair<ll, ll>
#define re return 0
#define mii map<int, int>
#define input "ALONE.inp"
#define output "ALONE.out"
#define rf freopen(input, "r", stdin); freopen(output, "w", stdout)
using namespace std;
const int maxn = 5e5 + 5;
const int mod = 1e9 + 7;
const int base = 998244353;
const int base1 = 31;
const int SZ = 320;
const ll INF = 1e18;
void add(int &a, int b)
{
a += b;
if(a >= mod) a -= mod;
if(a < 0) a += mod;
}
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
int rand(int l, int r)
{
return uniform_int_distribution<int>(l, r) (rd);
}
int par[20][maxn], depth[maxn], mindepth[maxn];
int cha[maxn], a[maxn];
bool vis[maxn];
int cnt[maxn];
vi adj[maxn];
void DFS(int u)
{
for(auto v : adj[u])
{
if(v == par[0][u])
continue;
depth[v] = depth[u] + 1;
par[0][v] = u;
FOR(i, 1, 19)
par[i][v] = par[i - 1][par[i - 1][v]];
DFS(v);
}
}
int LCA(int u, int v)
{
if(depth[u] < depth[v])
swap(u, v);
int h = depth[u] - depth[v];
FOR1(i, 19, 0)
if((h >> i) & 1)
u = par[i][u];
if(u == v)
return u;
FOR1(i, 19, 0)
if(par[i][u] != par[i][v])
{
u = par[i][u];
v = par[i][v];
}
return par[0][u];
}
void solve(int u)
{
for(auto v : adj[u])
{
if(v == par[0][u])
continue;
solve(v);
mindepth[u] = min(mindepth[u], mindepth[v]);
cnt[u] += cnt[v];
}
if(mindepth[u] == depth[u])
{
vis[u] = 1;
if(cnt[u] == 0)
cnt[u] = 1;
}
}
int main()
{
fastio;
int n, k;
cin >> n >> k;
FOR(i, 1, n - 1)
{
int u, v;
cin >> u >> v;
adj[u].pb(v);
adj[v].pb(u);
}
FOR(i, 1, n)
cin >> a[i];
DFS(1);
FOR(i, 1, n)
{
if(cha[a[i]] == 0)
cha[a[i]] = i;
else
cha[a[i]] = LCA(cha[a[i]], i);
}
FOR(i, 1, n)
mindepth[i] = depth[cha[a[i]]];
solve(1);
int dem = 0;
FOR(i, 2, n)
dem += vis[i];
if(dem == 0)
{
cout << 0;
re;
}
dem = 0;
for(auto v : adj[1])
if(vis[v])
dem++;
if(dem != 1)
{
cout << (cnt[1] + 1) / 2;
re;
}
dem = 0;
for(auto v : adj[1])
{
if(vis[v])
continue;
if(cnt[v])
dem++;
}
if(dem == 0)
{
cout << (cnt[1] / 2) + 1;
re;
}
cout << (cnt[1] + 1) / 2;
re;
}
