#include <bits/stdc++.h>

using namespace std;
#define int long long
#define endl '\n'
#define PII pair<int, int>
const int N = 2e5 + 5;
int n, m, ans, vis[N], mx[N];
vector<int> e[N];
void dfs(int u, int fa, int ok)
{
    vis[u] |= ok;
    int cnt = 0;
    for (auto to : e[u])
        if (to != fa && !vis[to])
            cnt++;
    if (cnt || vis[u] == 0)
        ans++;
    else
        return;
    for (auto to : e[u])
        if (to != fa)
        {
            cnt -= vis[to] == 0;
            if (cnt >= 1)
                dfs(to, u, 0);
            else
                dfs(to, u, vis[u]);
            cnt += vis[to] == 0;
        }
}

void solve()
{
    cin >> n >> m;
    for (int i = 1; i < n; i++)
    {
        int u, v;
        cin >> u >> v;
        e[u].push_back(v);
        e[v].push_back(u);
    }
    for (int i = 1; i <= m; i++)
    {
        int x;
        cin >> x;
        vis[x] = 1;
    }
    dfs(1, 0, 0);
    cout << ans << endl;
}

signed main()
{
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    int t = 1;
    while (t--)
        solve();
    return 0;
}