#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pu push_back
#define ll long long
typedef pair <ll,ll> ii;
const int N=1e6;
long long mod=1e16;
ll n,s,q,e,h,t;
ll a[N+1],b[N+1],d[N+10],t_in[N+10],t_out[N+10],dist[N+10],dep[N+10];
ll tt[21][N+10],gt[21][N+10];
struct canh{
ll u,v,w;
};
canh c[N+10];
vector <ii> adj[N+10];
bool o[N+10];
void dfs(int u,int p){
t++;
t_in[u]=t;
for(int i=1;i<=20;i++){
tt[i][u]=tt[i-1][tt[i-1][u]];
}
d[u]=mod;
if(o[u]) d[u]=dist[u];
for(auto x:adj[u]){
ll v=x.fi,w=x.se;
if(v==p) continue;
dist[v]=dist[u]+w;
dep[v]=dep[u]+1;
tt[0][v]=u;
dfs(v,u);
d[u]=min(d[u],d[v]);
}
t_out[u]=t;
if(d[u]!=mod) gt[0][u]=d[u]-2*dist[u];
else gt[0][u]=mod;
}
bool totien(int u,int v){
if(t_in[u]<=t_in[v] and t_out[u]>=t_out[v]) return true;
return false;
}
void tinh(){
cin>>n>>s>>q>>h;
for(int i=1;i<n;i++){
ll u,v,w;
cin>>u>>v>>w;
adj[u].pu({v,w});
adj[v].pu({u,w});
c[i].u=u,c[i].v=v,c[i].w=w;
}
for(int i=1;i<=s;i++){
cin>>b[i];
o[b[i]]=true;
}
dep[h]=1;
dfs(h,0);
for(int i=1;i<n;i++){
if(t_in[c[i].v]<t_in[c[i].u]){
swap(c[i].u,c[i].v);
}
}
for(int i=1;i<=20;i++){
for(int j=1;j<=n;j++){
gt[i][j]=min(gt[i-1][j],gt[i-1][tt[i-1][j]]) ;
}
}
while(q--){
int i,u;
cin>>i>>u;
int v=c[i].v;
if(!totien(v,u)){
cout<<"escaped\n";
continue;
}
ll res=gt[0][v]+dist[u],rem=dist[u];
for(int i=20;i>=0;i--){
if(dep[tt[i][u]]>=dep[v]){
res=min(res,rem+gt[i][u]);
u=tt[i][u];
}
}
if(res<mod) cout<<res<<'\n';
else cout<<"oo\n";
}
}
int main(){
//freopen("jday.inp","r",stdin);
//freopen("jday.out","w",stdout);
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
tinh();
return 0;
}
//code của anh Nam đẹp trai nhất CHL
