CLERVT_setter.cpp

#include <bits/stdc++.h>
using namespace std;

const int MAX_N = 1e5 + 5;
const int MAX_K = 27;

int N, K, Q;
vector<int> g[MAX_N];
set<int> Gset;
vector<int> G;
map<int, int> pos;
int dist[MAX_K + 1][MAX_K + 1];
int dp[1 << MAX_K], ans;

void dfs(int src, int u, int p, int d) {
    if (Gset.count(u)) {
        if (src == K) {
            pos[u] = G.size();
            G.push_back(u);
        }
        dist[src][pos[u]] = dist[pos[u]][src] = d;
    }
    for (int v : g[u]) if (v != p)
        dfs(src, v, u, d + 1);
}

void solve() {
    dfs(K, 1, 0, 0);
    for (int i = 0; i < K; i++)
        dfs(i, G[i], 0, 0);

    ans = N - 1;
    for (int mask = 1; mask < (1 << K); mask++) {
        int last = __builtin_ctz(mask);
        int m = mask ^ (1 << last);
        if (m == 0) {
            dp[mask] = dist[K][last];
            ans ^= N - 1 - dp[mask];
            continue;
        }
        int last2 = __builtin_ctz(m);
        dp[mask] = dp[m] + dist[last][last2];
        ans ^= N - 1 - (dp[mask] + dist[K][last]) / 2;
    }
}

int main() {
    ios_base::sync_with_stdio(false); cin.tie(NULL);

    cin >> N;
    for (int i = 0; i < N - 1; i++) {
        int u, v; cin >> u >> v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    cin >> K;
    for (int i = 0; i < K; i++) {
        int x; cin >> x;
        Gset.insert(x);
    }
    
    solve();

    cout << ans << "\n";

    return 0;
}