#include <bits/stdc++.h>
using namespace std;
#define int long long
#pragma GCC optimize("O3,unroll-loops")
#define ii pair<int,int>
#define fir first
#define sec second
#define pb push_back
const int maxn=1e5;
int n,s,qu,st;
int bin[maxn+2][20],mn[maxn+2][20];
int dep[maxn+2],dp[maxn+2],dist[maxn+2];
vector<pair<int,int> >adj[maxn+2];
bool shop[maxn+2];
void dfs(int cur,int par,int jrk){
dp[cur]=1e18;
dep[cur]=dep[par]+1; bin[cur][0]=par;
dist[cur]=jrk;
if(shop[cur]){
dp[cur]=dist[cur];
}
for(auto [nxt,we] : adj[cur]){
if(par==nxt)continue;
dfs(nxt,cur,jrk+we);
dp[cur]=min(dp[cur],dp[nxt]);
}
for(auto [nxt,we] : adj[cur]){
if(par==nxt)continue;
// mn[nxt][0]=min(mn[nxt][0],dp[cur]-2*dist[cur]);
}
mn[cur][0]=1e18;
if(dp[cur]<1e18){
mn[cur][0]=min(mn[cur][0],dp[cur]-2*dist[cur]);
}
}
int lca(int u,int v){
if(dep[u]<dep[v])swap(u,v);
int slsh=dep[u]-dep[v];
for(int q=19;q>=0;q--){
if(slsh>=(1<<q)){
u=bin[u][q];
slsh-=(1<<q);
}
}
if(u==v)return u;
for(int q=19;q>=0;q--){
if(bin[u][q]!=bin[v][q]){
u=bin[u][q],v=bin[v][q];
}
}
return bin[u][0];
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
cin>>n>>s>>qu>>st;
ii edge[n+1];
for(int q=1;q<n;q++){
int u,v,w;
cin>>u>>v>>w;
adj[u].pb({v,w});
adj[v].pb({u,w});
edge[q]={u,v};
}
for(int q=1;q<=s;q++){
int x; cin>>x;
shop[x]=true;
}
dfs(st,0,0);
for(int q=1;q<=19;q++){
for(int w=1;w<=n;w++){
bin[w][q]=bin[bin[w][q-1]][q-1];
mn[w][q]=min(mn[w][q-1],mn[bin[w][q-1]][q-1]);
}
}
while(qu--){
int jln,cur;
cin>>jln>>cur;
int idx=edge[jln].fir;
if(dep[edge[jln].fir]<dep[edge[jln].sec]){
idx=edge[jln].sec;
}
if(lca(idx,cur)!=idx){
cout<<"escaped"<<endl;
continue;
}
int ans=1e18;
int slsh=dep[cur]-dep[idx]+1;
int u=cur;
for(int q=19;q>=0;q--){
if(slsh>=(1<<q)){
int cost=mn[u][q]+dist[cur];
//cout<<u<<" "<<q<<" "<<mn[u][q]<<endl;
ans=min(ans,cost);
u=bin[u][q];
slsh-=(1<<q);
}
}
if(ans==1e18){
cout<<"oo"<<endl;
}
else{
cout<<ans<<endl;
}
}
}
