/* should pass subtasks 1, 2, 3 */
#include <iostream>
#include <vector>
using namespace std;
typedef long long ll;
pair<int, int> make_edge (int u, int v) {
return make_pair(min(u, v), max(u, v));
}
const int maxn = 100005;
const ll inf = 1LL << 60;
vector<pair<int, ll>> adj [maxn];
bool is_store [maxn];
void query_dfs (int vertex, int parent, int root, pair<int, int> forbidden, ll cur_dist, ll &ans) {
if (vertex == root) {
ans = -1;
}
if (is_store[vertex]) {
ans = min(cur_dist, ans);
}
for (pair<int, ll> nxt : adj[vertex]) {
if (nxt.first != parent && make_edge(vertex, nxt.first) != forbidden) {
query_dfs(nxt.first, vertex, root, forbidden, cur_dist + nxt.second, ans);
}
}
}
ll query (int vertex, int root, pair<int, int> forbidden) {
ll ans = inf;
query_dfs(vertex, -1, root, forbidden, 0, ans);
return ans;
}
int main () {
int vertexc, storec, queryc, root;
cin >> vertexc >> storec >> queryc >> root;
vector<pair<int, int>> edges;
for (int i = 0; i < vertexc - 1; i++) {
int u, v, w;
cin >> u >> v >> w;
adj[u].push_back(make_pair(v, w));
adj[v].push_back(make_pair(u, w));
edges.push_back(make_edge(u, v));
}
for (int i = 0; i < storec; i++) {
int x;
cin >> x;
is_store[x] = true;
}
for (int i = 0; i < queryc; i++) {
int forb_id, cur_vertex;
cin >> forb_id >> cur_vertex;
ll ans = query(cur_vertex, root, edges[forb_id - 1]);
if (ans == -1) {
cout << "escaped" << '\n';
} else if (ans == inf) {
cout << "oo" << '\n';
} else {
cout << ans << '\n';
}
}
}
