#include <bits/stdc++.h>
#define int long long
#define sz(a) (int)a.size()
#define all(a) a.begin(), a.end()
using namespace std;
const int LOG=24;
int n,s,e,q;
vector<vector<pair<int,int>>> neigh;
vector<bool> sp;
vector<int> depth;
vector<vector<int>> up;
vector<vector<int>> down;
vector<vector<pair<int,int>>> parent;
void dfs(int x, int p){
if(sp[x]) down[x][0]=0;
for (auto u : neigh[x])
{
if(u.first==p) continue;
parent[u.first][0]={x,u.second};
depth[u.first]=depth[x]+1;
dfs(u.first, x);
down[x][0]=min(down[x][0],down[u.first][0]+u.second);
}
}
int lca(int a, int b){
if(depth[a]>depth[b]) swap(a,b);
int d=depth[b]-depth[a];
for (int j = LOG-1; j >= 0; j--)
{
if(d&(1<<j)) b=parent[b][j].first;
}
if(a==b) return a;
for (int j = LOG-1; j >= 0; j--)
{
if(parent[a][j].first!=parent[b][j].first) a=parent[a][j].first,b=parent[b][j].first;
}
return parent[a][0].first;
}
signed main() {
ios_base::sync_with_stdio(false); cin.tie(nullptr);
cin>>n>>s>>q>>e;
neigh.resize(n);
depth.resize(n,0);
sp.resize(n,false);
down.resize(n,vector<int>(LOG,1e15));
parent.resize(n,vector<pair<int,int>>(LOG));
vector<pair<int,int>> edge(n-1);
e--;
for (int i = 0; i < n-1; i++)
{
int a,b,w; cin >> a >> b >> w;
a--; b--;
edge[i]={a,b};
neigh[a].push_back({b,w});
neigh[b].push_back({a,w});
}
for (int i = 0; i < s; i++){
int x; cin >> x;
sp[x-1]=true;
}
parent[e][0]={e,0};
depth[e]=0;
dfs(e,-1);
for (int j = 1; j < LOG; j++)
{
for (int i = 0; i < n; i++)
{
parent[i][j]={parent[parent[i][j-1].first][j-1].first,parent[parent[i][j-1].first][j-1].second+parent[i][j-1].second};
down[i][j]=min(down[i][j-1],down[parent[i][j-1].first][j-1]+parent[i][j-1].second);
}
}
for (int i = 0; i < q; i++)
{
int I; cin >> I; I--;
int r; cin >> r; r--;
int a=edge[I].first; int b=edge[I].second;
if(depth[b]<depth[a]) swap(a,b);
if(lca(b,r)!=b){
cout << "escaped\n";
continue;
}
int d=depth[r]-depth[b];
int dst=0;
int x=r;
int mn=1e12;
for (int j = LOG-1; j >= 0; j--)
{
if(d&(1<<j)){
mn=min(down[x][j]+dst,mn);
dst+=parent[x][j].second;
x=parent[x][j].first;
}
}
mn=min(down[x][0]+dst,mn);
if(mn==1e12) cout << "oo\n";
else cout << mn << "\n";
}
return 0;
}
