#include<bits/stdc++.h>
using namespace std;
const int N=1e5+10;
const int M=1<<18;
vector<pair<int,long long>> adj[N];
int ti,in[N],out[N],pa[N],dep[N],top[N],sz[N];
bool sh[N];
//distance from root, constant c[x]=min(d[shop])-2*d[x], dp[i]=minimum distance from root to shop in subtree of node i
long long d[N],c[N],dp[N],s[M];
pair<int,int> edge[N];
void build(int l,int r,int idx){
s[idx]=LLONG_MAX;
if(l==r) return;
int m=(l+r)/2;
build(l,m,idx*2);
build(m+1,r,idx*2+1);
}
void update(int l,int r,int idx,int a,int b){
if(a<l || a>r) return;
if(l==r){
s[idx]=b;
return;
}
int m=(l+r)/2;
update(l,m,idx*2,a,b);
update(m+1,r,idx*2+1,a,b);
s[idx]=min(s[idx*2],s[idx*2+1]);
}
long long query(int l,int r,int idx,int a,int b){
if(b<l || a>r) return LLONG_MAX;
if(a<=l && b>=r) return s[idx];
int m=(l+r)/2;
return min(query(l,m,idx*2,a,b),query(m+1,r,idx*2+1,a,b));
}
void findsz(int u,int p=0){
sz[u]=1;
int tmp=sz[p];
sz[p]=0;
for(int i=0;i<adj[u].size();i++){
auto [v,w]=adj[u][i];
if(v==p) continue;
dep[v]=dep[u]+1;
findsz(v,u);
sz[u]+=sz[v];
if(sz[v]>sz[adj[u][0].first]) swap(adj[u][i],adj[u][0]);
}
sz[p]=tmp;
}
void dfs(int u,int p=-1){
in[u]=++ti;
for(auto [v,w]:adj[u]){
if(v==p) continue;
pa[v]=u;
d[v]=d[u]+w;
dfs(v,u);
if(v==adj[u][0].first) top[v]=top[u];
else top[v]=v;
}
out[u]=ti;
}
void efs(int u,int p=-1){
if(sh[u]) dp[u]=d[u];
else dp[u]=LLONG_MAX;
for(auto [v,w]:adj[u]){
if(v==p) continue;
efs(v,u);
if(dp[v]!=LLONG_MAX) dp[u]=min(dp[u],dp[v]);
}
}
long long path(int u,int v){
long long ans=LLONG_MAX;
while(top[u]!=top[v]){
if(dep[top[u]]>dep[top[v]]) swap(u,v);
ans=min(ans,query(1,ti,1,in[top[v]],in[v]));
v=pa[top[v]];
}
if(dep[u]>dep[v]) swap(u,v);
ans=min(ans,query(1,ti,1,in[u],in[v]));
return ans;
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
int n,s,q,e;
cin>>n >>s >>q >>e;
for(int i=0;i<n-1;i++){
int a,b;
long long c;
cin>>a >>b >>c;
adj[a].push_back({b,c});
adj[b].push_back({a,c});
edge[i+1]={a,b};
}
for(int i=0;i<s;i++){
int inp;
cin>>inp;
sh[inp]=true;
}
findsz(e);
dfs(e);
efs(e);
// for(int i=1;i<=n;i++) cout<<sh[i] <<" ";
// cout<<"\n";
// for(int i=1;i<=n;i++) cout<<dp[i] <<" ";
// cout<<"\n";
build(1,ti,1);
for(int i=1;i<=n;i++){
if(dp[i]!=LLONG_MAX) c[i]=dp[i]-2LL*d[i];
else c[i]=LLONG_MAX;
update(1,ti,1,in[i],c[i]);
}
while(q--){
int clo,f;
cin>>clo >>f;
auto [hi,lo]=edge[clo];
if(pa[lo]!=hi) swap(lo,hi);
if(!(in[f]>=in[lo] && out[f]<=out[lo])){
cout<<"escaped\n";
continue;
}
if(dp[lo]==LLONG_MAX){
cout<<"oo\n";
continue;
}
long long ans=d[f]+path(lo,f);
cout<<0 <<"\n";
}
}
