#include <iostream>
#include <vector>
#include <set>
#include <queue>
using namespace std;
const int N=1e5+10;
pair<int,int> qp[N];
pair<int,int> ed[N];
vector<pair<int,int>> ma[N],query[N],adj[N];
int ans[N],shop[N];
long long dist[N];
set<int> cur;
void dfs(int x,int p=-1)
{
for(auto [ind,bl]:query[x])
if(cur.find(bl)==cur.end())
ans[ind]=1;
for(auto [y,ind]:ma[x])
{
if(y!=p)
{
cur.insert(ind);
dfs(y,x);
cur.erase(ind);
}
}
}
int main()
{
int n,s,q,e;
cin>>n>>s>>q>>e;
// n is Number of villages
// s is number of villages with shops
// q is queries
// e is the exit village
for(int i=1;i<n;i++)
{
int a,b,w;
cin>>a>>b>>w;
ed[i].first=a;
ed[i].second=b;
ma[a].push_back({b,i});
adj[a].push_back({b,w});
// Edge between a and b with length w
ma[b].push_back({a,i});
adj[b].push_back({a,w});
}
int sp;
for(int i=0;i<s;i++)
{
cin>>sp;
shop[sp]=1;
}
for(int i=0;i<q;i++)
{
int r,l;
cin>>r>>l;
qp[i]={l,r};
query[l].push_back({i,r});
}
dfs(e);
for(int j=0;j<q;j++)
{
if(ans[j])
{
cout<<"escaped\n";
}
else if(shop[qp[j].first])
{
cout<<0<<endl;
}
else
{
for(int i=1;i<=n;i++)
dist[i]=1e17;
long long anp=1e17;
int sv=qp[j].first;
int ca=ed[qp[j].second].first;
int cb=ed[qp[j].second].second;
dist[sv]=0;
bool lp=0;
priority_queue<pair<long long,int>,vector<pair<long long,int>>,greater<pair<long long,int>>> pq;
pq.push({dist[sv],sv});
while(pq.size())
{
auto it =pq.top();
pq.pop();
if(shop[it.second])
{
lp=1;
cout<<it.first<<endl;
break;
}
if(dist[it.second]==it.first)
{
for(auto [nv,ew]:adj[it.second])
{
if((nv==ca and it.second==cb) or (nv==cb and it.second==ca))
continue;
if(dist[nv]>(it.first+(long long)ew))
{
dist[nv]=it.first+(long long)ew;
pq.push({dist[nv],nv});
}
}
}
}
if(!lp)
cout<<"oo\n";
}
}
return 0;
}
