#include <bits/stdc++.h> using namespace std; #define all(x) x.begin(), x.end() const int mxN = 10005; vector<pair<int, int>> adj[mxN]; set<int> en_time[mxN], st_time[mxN]; int ans = 0; void dfs(int u = 1, int par = 0, int tim = mxN){ ans += 1; for(auto [v, t] : adj[u]){ if(v == par) continue; if((int) st_time[t].size() == 0) continue; if((int) *st_time[t].begin() > tim) continue; auto lb = en_time[t].lower_bound(tim); if(lb == en_time[t].end()) --lb; dfs(v, u, min(*lb, tim)); } } signed main(){ ios::sync_with_stdio(0); cin.tie(nullptr); cout.tie(nullptr); int n, m, q; cin >> n >> m >> q; vector<int> on(n + 5, 0); for(int i = 0, u, v; i < n - 1; ++i){ cin >> u >> v; adj[u].push_back({v, i + 1}); adj[v].push_back({u, i + 1}); } for(int i = 0, x; i < m; ++i){ cin >> x; on[x] ^= 1; if(on[x]){ st_time[x].insert(i); }else{ en_time[x].insert(i); } } for(int i = 0; i < n; ++i){ if((int) en_time[i + 1].size() == 0){ en_time[i + 1].insert(mxN); } } int x; cin >> x; dfs(x); cout << ans << "\n"; return 0; }