#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define fi first
#define se second
const ll MAXN=4e5+5,INF=1e18,MOD=1e9+7,MAXV=4e5+2;
ll n,m,i,j,k,p,dem,cnt,ans,S,Q,root,dtr[MAXN],shop[MAXN],mark[MAXN],preshop[MAXN],par[MAXN],dist[MAXN],chain[MAXN],headchain[MAXN],st[MAXN],en[MAXN],cntchain=1,de[MAXN],sz[MAXN];
vector<pair<ll,ll>> adj[MAXN];
pair<ll,ll> edge[MAXN];
ll dfs(ll st){
sz[st]=1;
if(shop[st]&1)
preshop[st]=st;
for(auto x:adj[st]){
if(de[x.fi]) continue;
de[x.fi]=de[st]+1;
dtr[x.fi]=dtr[st]+x.se;
par[x.fi]=st;
preshop[x.fi]=preshop[st];
dist[st]=min(dist[st],dfs(x.fi)+x.se);
sz[st]+=sz[x.fi];
}
if(shop[st]&1)
dist[st]=0;
return dist[st];
}
void HLD(ll u){
if(!headchain[cntchain])
headchain[cntchain]=u;
chain[u]=cntchain;
ll v=-1;
for(auto x:adj[u])
if(!chain[x.fi]&&(u==-1||sz[x.fi]>sz[v])) v=x.fi;
if(v>0) HLD(v);
for(auto x:adj[u]){
if(!chain[x.fi]){
cntchain++;
HLD(x.fi);
}
}
en[u]=cntchain;
}
ll lca(ll u,ll v){
if(en[u]>en[v]&&chain[u]<chain[v]) return u;
else if(en[u]<en[v]&&chain[u]>chain[v]) return v;
while(chain[u]!=chain[v]){
if(chain[u]>chain[v])
u=par[headchain[chain[u]]];
else v=par[headchain[chain[v]]];
}
return (de[u]<de[v]?u:v);
}
ll tinh(ll u,ll v){
return de[u]+de[v]-2*de[lca(u,v)];
}
void check(ll u,ll st){
ll stchain=chain[u],enchain=en[u],cur=preshop[st];
if(cur>0&&de[cur]>=de[u])
ans=min(ans,dtr[st]-dtr[cur]);
for(ll i=stchain;i<=enchain;i++){
if(de[par[headchain[i]]]<de[u]) continue;
ans=min(ans,dist[par[headchain[i]]]+dtr[par[headchain[i]]]+dtr[st]-2*dtr[lca(st,par[headchain[i]])]);
}
}
int main(){
ios::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
cin>>n>>S>>Q>>root;
for(i=1;i<n;i++){
ll u,v,c;
cin>>u>>v>>c;
edge[i]={u,v};
adj[u].pb({v,c});
adj[v].pb({u,c});
}
for(i=1;i<=S;i++)
cin>>k,shop[k]=1;
de[root]=1;
fill(dist+1,dist+n+1,INF);
dfs(root);
HLD(root);
for(i=1;i<=Q;i++){
ll block,E;
cin>>block>>E;
ll u=edge[block].fi,v=edge[block].se;
if(de[u]<de[v]) swap(u,v);
if(tinh(u,E)+tinh(v,root)+1==tinh(E,root)){
ans=min(dist[E],dist[u]-dtr[u]+dtr[E]);
check(u,E);
if(ans>=INF){
cout<<"oo"<<'\n';
}
else cout<<ans<<'\n';
}
else cout<<"escaped"<<'\n';
}
}
