#include<bits/stdc++.h>
using namespace std;
typedef vector<int> vi;
typedef vector<vi> vvi;
vi isShop, padre, level;
vector<pair<int, int>> edges;
vvi listaAdy, weights, dp;
int N, Q, E, S, LG;
void dfs(int nodo){
for (int e = 0; e < listaAdy[nodo].size(); ++e){
int vecino = listaAdy[nodo][e];
int dist = weights[nodo][e];
if(padre[nodo] == vecino) continue;
padre[vecino] = nodo;
level[vecino] = level[nodo]+1;
dfs(vecino);
}
}
int KthAncestor(int nodo, int K){
for(int i = LG-1; i >= 0; --i){
if((1 << i)<= K){
K^=(1 << i);
nodo = dp[nodo][i];
}
}
return nodo;
}
void preprocess(){
dfs(E);
dp = vvi(N, vi(LG));
for(int i = 0; i < N; ++i){
dp[i][0] = padre[i];
}
for(int h = 1; h < LG; ++h){
for(int nodo = 0; nodo < N; ++nodo){
dp[nodo][h] = dp[dp[nodo][h-1]][h-1];
}
}
}
int getSon (pair<int, int> p){
int a = p.first;
int b = p.second;
if (a == padre[b]) return b;
return a;
}
long long dijkstra(int origin, pair<int, int> take){
queue<pair<long long int, pair<int, int>>> PQ;
long long int ans = 1e18;
int u = take.first; int v = take.second;
PQ.push({0, {origin, -1}});
while(!PQ.empty()){
pair<long long int, pair<int, int>> act;
act = PQ.front(); PQ.pop();
long long int dist = act.first;
int nodo = act.second.first;
int padre = act.second.second;
if(isShop[nodo]){
ans = min(ans, dist);
continue;
}
for(int e = 0; e < listaAdy[nodo].size(); ++e){
int vecino = listaAdy[nodo][e];
int w = weights[nodo][e];
if((vecino == u and nodo == v) or (vecino == v and nodo == u)) continue;
if(vecino == padre) continue;
PQ.push({(dist+(long long)w), {vecino, nodo}});
}
}
return ans;
}
int main(){
cin >> N >> S >> Q >> E; E--;
int a, b, w, I, R;
LG = log2(N) + 2;
listaAdy = vvi(N);
weights = vvi(N);
level = vi(N);
padre = vi(N);
padre[E] = E;
level[E] = 0;
isShop = vi(N, 0);
for(int i = 1; i < N; ++i){
cin >> a >> b >> w;
a--; b--;
edges.push_back({a, b});
listaAdy[a].push_back(b);
listaAdy[b].push_back(a);
weights[a].push_back(w);
weights[b].push_back(w);
}
for(int i = 0; i < S; ++i){
cin >> a; a--;
isShop[a] = 1;
}
preprocess();
while(Q--){
cin >> I >> R; I--; R--;
int son = getSon(edges[I]);
int d = level[R] - level[son];
if(KthAncestor(R, d) != son){
cout << "escaped" << endl;
continue;
}
long long ans = dijkstra(R, edges[I]);
if(ans == 1e18) cout << "oo" << endl;
else cout << ans << endl;
}
return 0;
}
