#include<bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define pb push_back
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
template<typename T> bool chkmax(T &x,T y){return x<y?x=y,1:0;}
template<typename T> bool chkmin(T &x,T y){return x>y?x=y,1:0;}
const ll inf=1e18;
int n,s,q,e,x[100005],y[100005],w[100005],id[100005],is[100005];
int root[100005],tsz,ls[2000005],rs[2000005],dfn[100005],dfo[100005],T;
ll dep[100005],st[2000005],lzy[2000005];
vector<pii> adj[100005];
void build(int&c,int l,int r){
c=++tsz;
if(l==r)return (void)(st[c]=(is[id[l]]?dep[id[l]]:inf));
int m=(l+r)/2;
build(ls[c],l,m);
build(rs[c],m+1,r);
st[c]=min(st[ls[c]],st[rs[c]]);
}
void modify(int p,int&c,int l,int r,int tl,int tr,int v){
if(tl>tr||l>tr||r<tl) return;
c=++tsz; ls[c]=ls[p]; rs[c]=rs[p]; st[c]=st[p]; lzy[c]=lzy[p];
if(tl<=l&&r<=tr){st[c]+=v; lzy[c]+=v; return;}
int m=(l+r)/2;
modify(ls[p],ls[c],l,m,tl,tr,v);
modify(rs[p],rs[c],m+1,r,tl,tr,v);
st[c]=min(st[ls[c]],st[rs[c]])+lzy[c];
}
ll query(int c,int l,int r,int tl,int tr){
if(tl>tr||l>tr||r<tl) return inf;
if(tl<=l&&r<=tr) return st[c];
int m=(l+r)/2;
return min(query(ls[c],l,m,tl,tr),query(rs[c],m+1,r,tl,tr))+lzy[c];
}
void dfs0(int u,int p){
dfn[u]=++T,id[T]=u;
for(auto e:adj[u]) if(e.fi!=p) dep[e.fi]=dep[u]+e.se,dfs0(e.fi,u);
dfo[u]=T;
}
void dfs1(int u,int p,int wu){
if(p!=0) modify(root[p],root[u],1,T,dfn[u],dfo[u],-2*wu);
for(auto e:adj[u]) if(e.fi!=p) dfs1(e.fi,u,e.se);
}
bool anc(int u,int v){return dfn[u]<=dfn[v]&&dfo[v]<=dfo[u];}
void deb(int c,int l,int r){
printf("st:%d %d %d %d %d\n",c,l,r,ls[c],rs[c]);
if(l==r){printf("%lld ",st[c]); return;}
int m=(l+r)/2;
deb(ls[c],l,m);
deb(rs[c],m+1,r);
}
int main(){
scanf("%d%d%d%d",&n,&s,&q,&e);
for(int i=1;i<n;i++){
scanf("%d%d%d",&x[i],&y[i],&w[i]);
adj[x[i]].pb(mp(y[i],w[i]));
adj[y[i]].pb(mp(x[i],w[i]));
}
for(int i=1,r;i<=s;i++) scanf("%d",&r),is[r]=1;
dfs0(1,0); build(root[1],1,T); dfs1(1,0,0);
//deb(root[1],1,T);
while(q--){
int i,r;scanf("%d%d",&i,&r);
int u=x[i],v=y[i];
if(dep[u]>dep[v]) swap(u,v);
if(anc(v,e)==anc(v,r)){printf("escaped\n"); continue;}
ll ans=dep[r];
if(anc(v,r)) ans+=query(root[r],1,T,dfn[v],dfo[v]);
else ans+=min(query(root[r],1,T,1,dfn[v]-1),query(root[r],1,T,dfo[v]+1,T));
if(ans>=1e17) printf("oo\n");
else printf("%lld\n",ans);
}
return 0;
}
