#include <bits/stdc++.h>
using namespace std;
#define ll long long
int n;
vector<bool> shop;
vector<ll> dep,magic;
vector<int> parents,dist,tin,tout;
vector<vector<pair<int,int>>> graf;
int tim=0;
void dfs(int x,int parent=-1,ll deph=0,int dista=0)
{
tin[x]=++tim;
parents[x]=parent;
dep[x]=deph;
dist[x]=dista;
for(auto [node,l]:graf[x])
{
if(node==parent) continue;
dfs(node,x,deph+l,dista+1);
}
if(shop[x])
{
magic[x]=dep[x];
}
else magic[x]=1e17;
for(auto [node,l]:graf[x])
{
if(node==parent) continue;
magic[x]=min(magic[x],magic[node]);
}
tout[x]=tim;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int s,q,e;
cin>>n>>s>>q>>e;
graf=vector<vector<pair<int,int>>>(n);
magic=vector<ll>(n);
vector<pair<int,int>> edges(n-1);
int a,b,c;
for(int i=0;i<n-1;i++)
{
cin>>a>>b>>c;
graf[--a].push_back({--b,c});
graf[b].push_back({a,c});
edges[i]={a,b};
}
dep=vector<ll>(n,0);
shop=vector<bool>(n,0);
parents=vector<int>(n);
dist=vector<int>(n);
for(int i=0;i<s;i++)
{
cin>>a;
shop[--a]=1;
}
tin=vector<int>(n);
tout=vector<int>(n);
dfs(--e);
vector<vector<int>> logdist(n,vector<int>(log2(n)+1,-1));
vector<vector<ll>> magicdist(n,vector<ll>(log2(n)+1,1e17));
for(int i=0;i<n;i++)
{
if(magic[i]==1e17) continue;
magic[i]-=dep[i]*2;
}
for(int i=0;i<n;i++)
{
logdist[i][0]=parents[i];
magicdist[i][0]=magic[i];
}
for(int i=1;i<=log2(n);i++)
{
for(int j=0;j<n;j++)
{
int half=logdist[j][i-1];
if(half==-1)
{
logdist[j][i]=-1;
continue;
}
else
{
logdist[j][i]=logdist[half][i-1];
magicdist[j][i]=min(magicdist[j][i-1],magicdist[half][i-1]);
}
}
}
int I,R;
int i1,i2;
for(int i=0;i<q;i++)
{
cin>>I>>R;
I--;
R--;
if(dist[edges[I].first]<dist[edges[I].second])
{
i1=edges[I].second;
i2=edges[I].first;
}
else
{i1=edges[I].first;
i2=edges[I].second;}
if(tin[i1]>tin[R] || tout[i1]<tout[R])
{
cout<<"escaped\n";
continue;
}
ll ans=dep[R];
ll magi=magic[R];
int k=dist[R]-dist[i2];
for(int j=0;j<=log(n);j++)
{
if(k&(1<<j))
{
magi=min(magi,magicdist[R][j]);
R=logdist[R][j];
}
}
if(magi==1e17) cout<<"oo\n";
else cout<<magi+ans<<'\n';
}
}
