/*
* prep: 4.3
*/
#include<bits/stdc++.h>
using namespace std;
#define fr first
#define sc second
#define pb push_back
#define mp make_pair
#define ll long long
#ifdef LOCAL
#define eprintf(...) {fprintf(stderr, __VA_ARGS__);fflush(stderr);}
#else
#define eprintf(...) 42
#endif
int n,s,q,e;
vector<pair<int,int>>adj[100002];
pair<int,int>id[100002];
ll shop[100002], dp[100002], depth[100002];
int up[100002][20];
ll dp2[100002][20];
ll nq[100002];
void DepthFirstSearch(int u, int p){
dp[u] = (ll)1e15;
dp2[u][0] = (ll)1e15;
depth[u] = depth[p]+1;
up[u][0]=(u == e ? e : p);
if (shop[u])dp[u]=0;
for (auto edge: adj[u]){
if (edge.fr == p)continue;
nq[edge.fr] = nq[u]+edge.sc;
DepthFirstSearch(edge.fr, u);
dp[u] = min(dp[u], dp[edge.fr] + edge.sc);
}
dp2[u][0] = dp[p] - nq[p];
}
void build(){
for (int level = 1; level < 20; ++level){
for (int node = 1; node <= n; ++node){
up[node][level] = up[up[node][level-1]][level-1];
dp2[node][level] = min(dp2[node][level - 1], dp2[up[node][level-1]][level-1]);
}
}
}
int LowestCommonAncestor(int a, int b){
if (depth[a] < depth[b])swap(a,b);
int k = depth[a] -depth[b];
for (int lvl = 19; lvl >= 0; --lvl){
if ((1 << lvl) & k){
a = up[a][lvl];
}
}
if(a == b)return a;
for (int i = 19; i>=0; --i){
if(up[a][i] != up[b][i]){
a = up[a][i];
b = up[b][i];
}
}
return up[a][0];
}
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
cin >> n >> s >> q >> e;
for (int i = 0; i + 1 < n; i++){
int a,b,w;cin >> a >> b >> w;
adj[a].pb(mp(b,w));
adj[b].pb(mp(a,w));
id[i] = mp(a,b);
}
for (int i= 0; i < s; i++){
int x; cin >> x;
shop[x] = 1;
}
depth[0]=-1;
dp[0] = (int)1e9;
DepthFirstSearch(e,0);
build();
for (int i = 0; i < q; i++){
int blocked, start;
cin >> blocked >> start;
if(start==e){cout<<"escaped"<<'\n';continue;}
int lower = (up[id[blocked-1].fr][0] == id[blocked-1].sc ? id[blocked-1].fr : id[blocked-1].sc);
//cout<<LowestCommonAncestor(lower, start)<<endl;
if(LowestCommonAncestor(start, lower) == lower){
//find minimal shop
if(shop[start]){
cout<<0<<endl;
continue;
}
int k = depth[start] - depth[lower];
int h = nq[start];
ll ans = (ll)1e15;
ans = dp[start];
for (int lvl = 19; lvl >= 0; --lvl){
if ((1 << lvl) & k){
ans = min(ans, dp2[start][lvl]);
start = up[start][lvl];
}
}
if(ans + h >=(ll)1e14)cout<<"oo"<<endl;
else cout<<ans + h<<'\n';
}else{
cout<<"escaped"<<'\n';
}
}
return 0;
}
