#include <bits/stdc++.h>
using namespace std;
#define all(v) v.begin(), v.end()
#define endl '\n'
#define pl(var) " [" << #var << ": " << (var) << "] "
#define ll long long
vector<vector<pair<int, int>>> adj;
vector<int> tin, tout;
vector<ll int> dist, dp1, dp2;
vector<bool> shop;
int timer = 0;
void dfs(int u, int par, ll int dis) {
dist[u] = dis;
tin[u] = timer++;
for (auto [v, w] : adj[u]) {
if (v == par) continue;
dfs(v, u, dis + w);
}
if (shop[u]) dp1[u] = 0;
else dp1[u] = 1e16;
for (auto [v, _] : adj[u]) {
if (v == par) continue;
dp1[u] = min(dp1[u], dp1[v] + 1);
}
tout[u] = timer - 1;
}
bool is_acc(int acc, int child) {
if (acc == child) return 1;
return tin[acc] < tin[child] && tin[child] <= tout[acc];
}
void solve() {
int n, s, q, e; cin >> n >> s >> q >> e;
adj.resize(n);
dp1.resize(n);
dp2.resize(n);
tin.resize(n);
tout.resize(n);
dist.resize(n);
shop.resize(n);
vector<pair<pair<int, int>, int>> edges;
for (int i = 0; i < n - 1; i++) {
int a, b; cin >> a >> b;
int c; cin >> c;
a--, b--;
adj[a].emplace_back(b, c);
adj[b].emplace_back(a, c);
edges.emplace_back(make_pair(a, b), c);
}
for (int i = 0; i < s; i++) {
int a; cin >> a;
shop[a - 1] = 1;
}
// e is the root
dfs(e - 1, e - 1, 0);
// cout << pl(tin[0]) << endl;
while (q--) {
int a, b; cin >> a >> b;
a--, b--;
pair<int, int> edge = edges[a].first;
// cout << pl(edge.first) << pl(edge.second) << pl(is_acc(edge.first, b)) << pl(is_acc(edge.second, b)) << pl(b) << endl;
if (is_acc(edge.first, b) && is_acc(edge.second, b)) {
cout << 0 << endl;
} else {
cout << "escaped" << endl;
}
}
}
int main() {
// freopen(".in", "r", stdin);
// freopen(".out", "w", stdout);
ios::sync_with_stdio(false);
cin.tie(nullptr);
int T = 1;
// cin >> T;
while (T--)
solve();
}
