#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
typedef long long ll;
const ll INF = 1e16;
struct Edge { int to, weight, id; };
vector<Edge> adj[100005];
pair<int, int> edges[100005];
int n, s, q, e_root;
bool has_shop[100005];
int tin[100005], tout[100005], timer;
ll dist[100005];
int up[100005][20];
ll best_shop[100005], dp[100005][20];
// DFS: Masofalar, LCA va Subtree oraliqlarini hisoblash
void dfs_prep(int u, int p, ll d) {
tin[u] = ++timer;
up[u][0] = p;
dist[u] = d;
best_shop[u] = (has_shop[u] ? d : INF);
for (auto& edge : adj[u]) {
if (edge.to != p) {
dfs_prep(edge.to, u, d + edge.weight);
best_shop[u] = min(best_shop[u], best_shop[edge.to]);
}
}
tout[u] = timer;
}
// Binary Lifting uchun tayyorgarlik
void dfs_dp(int u, int p) {
dp[u][0] = best_shop[u] - 2 * dist[u];
for (int i = 1; i < 20; i++) {
up[u][i] = up[up[u][i - 1]][i - 1];
dp[u][i] = min(dp[u][i - 1], dp[up[u][i - 1]][i - 1]);
}
for (auto& edge : adj[u]) {
if (edge.to != p) dfs_dp(edge.to, u);
}
}
bool is_ancestor(int u, int v) {
return tin[u] <= tin[v] && tout[u] >= tout[v];
}
int main() {
ios::sync_with_stdio(0); cin.tie(0);
cin >> n >> s >> q >> e_root;
for (int i = 1; i < n; i++) {
int u, v, w; cin >> u >> v >> w;
adj[u].push_back({v, w, i});
adj[v].push_back({u, w, i});
edges[i] = {u, v};
}
for (int i = 0; i < s; i++) { int c; cin >> c; has_shop[c] = true; }
dfs_prep(e_root, e_root, 0);
dfs_dp(e_root, e_root);
while (q--) {
int idx, r; cin >> idx >> r;
int u = edges[idx].first, v = edges[idx].second;
// Ildizga nisbatan qaysi biri pastroqda ekanini aniqlash
int child = (dist[u] > dist[v] ? u : v);
if (!is_ancestor(child, r)) {
cout << "escaped\n";
} else {
ll res = INF;
int curr = r;
// Binary lifting orqali child gacha bo'lgan yo'lda eng yaqin do'konni topish
for (int i = 19; i >= 0; i--) {
if (is_ancestor(child, up[curr][i])) {
res = min(res, dp[curr][i]);
curr = up[curr][i];
}
}
res = min(res, dp[curr][0]);
if (res > INF / 2) cout << "oo\n";
else cout << res + dist[r] << "\n";
}
}
return 0;
}
