#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int N=1e5+5;
const ll INF=1e18;
int n,s,q,e,tin[N],tout[N],t=0;
vector<pair<int,int>>adj[N];
pair<int,int>edg[N];
bool shop[N]{};
set<pair<int,int>>unu;
void dfs(int u=e,int p=0){
tin[u]=t++;
for(auto[v,c]:adj[u]){
if(v==p)continue;
dfs(v,u);
}
tout[u]=t++;
}
bool under(int u,int v){
return tin[v]<=tin[u]&&tout[u]<=tout[v];
}
ll f(int r){
ll res=INF;
priority_queue<tuple<ll,int,int>>pq;
pq.push({0,r,0});
while(!pq.empty()){
auto[sum,u,p]=pq.top();
pq.pop();
sum*=-1;
if(shop[u]){
res=min(res,sum);
continue;
}
for(auto[v,c]:adj[u]){
if(v==p||unu.count({u,v}))continue;
pq.push({-sum-c,v,u});
}
}
return res;
}
int main(){
ios_base::sync_with_stdio(0);cin.tie(0);
cin>>n>>s>>q>>e;
for(int i=1;i<=n-1;i++){
int a,b,w;
cin>>a>>b>>w;
adj[a].push_back({b,w});
adj[b].push_back({a,w});
edg[i]={a,b};
}
for(int i=0;i<s;i++){
int c;cin>>c;
shop[c]=1;
}
dfs();
while(q--){
int i,r;
cin>>i>>r;
auto[a,b]=edg[i];
if(!(under(r,a)&&under(r,b))){
cout<<"escaped\n";
continue;
}
unu.clear();
unu.insert({a,b});
unu.insert({b,a});
ll res=f(r);
if(res<INF){
cout<<res<<"\n";
}else{
cout<<"oo\n";
}
}
}
