#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int N=1e5+5,K=17;
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]{};
int par[N][K]{};
ll dis[N]{},lift[N][K];
ll dfs(int u=e,int p=0){
tin[u]=t++;
par[u][0]=p;
ll csd=(shop[u]?0:INF);
for(auto[v,c]:adj[u]){
if(v==p)continue;
dis[v]=dis[u]+c;
csd=min(csd,dfs(v,u)+c);
}
lift[u][0]=csd-dis[u];
tout[u]=t++;
return csd;
}
bool under(int u,int v){
return tin[v]<=tin[u]&&tout[u]<=tout[v];
}
ll f(int a,int b){
//cout<<a<<" "<<b<<"\n";
ll res=lift[b][0];
int u=b;
for(int i=K-1;i>=0;i--){
int v=par[u][i];
if(!v||dis[v]<dis[a])continue;
//cout<<"!"<<v<<"\n";
res=min(res,lift[par[u][0]][i]);
u=v;
}
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();
lift[0][0]=INF;
for(int i=1;i<K;i++){
for(int u=1;u<=n;u++){
int v=par[u][i-1];
par[u][i]=par[v][i-1];
}
}
for(int i=1;i<K;i++){
for(int u=1;u<=n;u++){
int v=par[u][i-1];
lift[u][i]=min(lift[u][i-1],lift[v][i-1]);
}
}
while(q--){
int i,r;
cin>>i>>r;
auto[a,b]=edg[i];
if(!(under(r,a)&&under(r,b))){
cout<<"escaped\n";
continue;
}
ll res=f((dis[a]>dis[b]?a:b),r);
if(res<INF/100){
cout<<res+dis[r]<<"\n";
}else{
cout<<"oo\n";
}
}
for(int i=0;i<K;i++){
//cout<<lift[5][i]<<"\n";
}
//cout<<dis[3];
}
