#include <bits/stdc++.h>
#define fio ios_base::sync_with_stdio(0);
using namespace std;
bool dfs(int i, int p, pair<int, int> snow, vector<vector<pair<int, int>>>& adj, int e, long long& dist, set<int>& shops, long long& minn){
if(i == e){
return true;
}
if(shops.count(i)){
minn = min(minn, dist);
}
int ok = false;
for(auto u : adj[i]){
int j = u.first;
int c = u.second;
if(j == p){
continue;
}
if((i == snow.first && j == snow.second) || (j == snow.first && i == snow.second)){
continue;
}
dist += c;
bool b = dfs(j, i, snow, adj, e, dist, shops, minn);
if(b){
ok = true;
}
dist -= c;
}
return ok;
}
int main()
{
fio
int n, s, q, e;
cin >> n >> s >> q >> e;
vector<vector<pair<int, int>>> adj(n+1);
vector<pair<int, int>> roads(n+1);
for(int i = 0; i < n-1; ++i){
int a, b, w;
cin >> a >> b >> w;
adj[a].push_back({b, w});
adj[b].push_back({a, w});
roads[i+1] = {a, b};
}
set<int> shops;
for(int i = 0; i< s; ++i){
int c;
cin >> c;
shops.insert(c);
}
for(int qw = 0; qw < q; ++qw){
int r, vil;
cin >> r >> vil;
long long dist = 0;
long long minn = LLONG_MAX;
if(dfs(vil, -1, roads[r], adj, e, dist, shops, minn)){
cout << "escaped\n";
}else{
if(minn == LLONG_MAX){
cout << "oo\n";
}else{
cout << minn << "\n";
}
}
}
return 0;
}
