/*
بسم الله الرحمن الرحيم
Author:
(:Muhammad Aneeq:)
*/
#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
using namespace std;
#define int long long
int const N=1e5+10,LG=18;
int par[N][LG]={};
int pa[N]={},h[N]={},co[N]={};
vector<int>shops;
int n,s,q,e;
vector<int>f;
vector<pair<int,int>>nei[N]={};
set<pair<int,int>>s1;
void precomp()
{
for (int i=1;i<=n;i++)
par[i][0]=pa[i];
for (auto [h,i]:s1)
for (int j=1;j<LG;j++)
if (par[i][j-1]!=0)
par[i][j]=par[par[i][j-1]][j-1];
}
void lift(int d,int& x)
{
for (int i=0;i<LG;i++)
{
if ((1<<i)&d)
x=par[x][i];
}
}
int LCA(int u,int v)
{
if (h[u]<h[v])
swap(u,v);
lift(h[u]-h[v],u);
if (u==v)
return u;
for (int i=LG-1;i>=0;i--)
{
if (par[u][i]==par[v][i])
continue;
u=par[u][i];
v=par[v][i];
}
return par[u][0];
}
void dfs(int n,int m=-1)
{
s1.insert({h[n],n});
for (auto [i,w]:nei[n])
{
if (i==m)
continue;
pa[i]=n;
h[i]=h[n]+1;
co[i]=co[n]+w;
dfs(i,n);
}
}
inline void solve()
{
cin>>n>>s>>q>>e;
vector<pair<int,int>>ed;
for (int i=1;i<n;i++)
{
int u,v,w;
cin>>u>>v>>w;
nei[u].push_back({v,w});
nei[v].push_back({u,w});
ed.push_back({u,v});
}
dfs(1);
precomp();
while (s--)
{
int x;
cin>>x;
shops.push_back(x);
}
sort(begin(shops),end(shops));
while (q--)
{
int i,r;
cin>>i>>r;
i--;
int u=ed[i].first,v=ed[i].second;
int z=LCA(r,e);
bool w=1;
if (((LCA(r,v)==v&&LCA(v,z)==z)&&(LCA(r,u)==u&&LCA(u,z)==z))||((LCA(e,v)==v&&LCA(v,z)==z)&&(LCA(e,u)==u&&LCA(u,z)==z)))
w=0;
if (w)
{
cout<<"escaped\n";
continue;
}
auto y=lower_bound(begin(shops),end(shops),r);
if (y!=shops.end()&&*y==r)
{
cout<<0<<endl;continue;
}
int ans=1e15+10;
for (auto j:shops)
{
int z=LCA(r,j);
bool w=1;
if (((LCA(r,v)==v&&LCA(v,z)==z)&&(LCA(r,u)==u&&LCA(u,z)==z))||((LCA(j,v)==v&&LCA(v,z)==z)&&(LCA(j,u)==u&&LCA(u,z)==z)))
w=0;
if (w)
ans=min(ans,co[r]+co[j]-2*co[z]);
}
if (ans==1e15+10)
cout<<"oo\n";
else
cout<<ans<<endl;
}
}
signed main()
{
ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
solve();
}
