// #include <bits/stdc++.h>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <map>
#include <unordered_map>
#include <vector>
#include <iomanip>
#include <string>
#include <queue>
#include <set>
#include <deque>
using namespace std;
#define endl "\n"
#define pb push_back
#define int long long
#define fi first
#define se second
const int N = 3e5 + 5, M = 1e9 + 7, LG = 20;
int n , A[N] , u , v , w , q , e , s , x , P[N] , dp[N] , I[N] , in = 1 , U[N] , V[N] , O[N] , sp[N][LG] , dep[N] , pr[N][LG];
bool vi[N];
vector<pair<int,int>> lis[N];
void dfs(int v , int par , int wi){
P[v] = par;
dp[v] = 1e18;
dep[v] = dep[par] + wi;
I[v] = in;
in++;
for (auto [u,w] : lis[v]){
if (u == par) continue;
dfs(u , v , w);
dp[v] = min(dp[v] , dp[u]);
}
if (vi[v]){
dp[v] = dep[v];
}
sp[v][0] = dp[v] - 2 * dep[v];
pr[v][0] = par;
O[v] = in;
in++;
}
void solve(){
cin >> n >> s >> q >> e;
dp[0] = 1e18;
for (int i=1 ; i<n ; i++){
cin >> u >> v >> w;
lis[u].pb({v,w});
lis[v].pb({u,w});
U[i] = u;
V[i] = v;
}
for (int i=1 ; i<=s ; i++){
cin >> x;
vi[x] = 1;
}
dfs(e , 0 , 0);
for (int j=1 ; j<LG ; j++){
for (int i=1 ; i<=n ; i++){
pr[i][j] = pr[pr[i][j-1]][j-1];
}
}
for (int j=1 ; j<LG ; j++){
for (int i=1 ; i<=n ; i++){
if (!pr[i][j]) continue;
sp[i][j] = min(sp[i][j-1] , sp[pr[i][j-1]][j-1]);
}
}
while(q--){
cin >> x >> v;
int u = -1;
if (P[U[x]] == V[x]){
u = U[x];
}else{
u = V[x];
}
if (I[v] >= I[u] && O[v] <= O[u]){
int ans = dp[v] - 2 * dep[v] , v1 = v;
for (int i=LG-1 ; i>=0 ; i--){
if (!pr[v][i]) continue;
int j = pr[v][i];
if (I[j] >= I[u] && O[j] <= O[u]){
v = pr[v][i];
ans = min(ans , sp[v][i]);
}
}
ans += dep[v1];
// cout << sp[5][1] << endl;
if (ans >= 1e15){
cout << "oo" << endl;
}else{
cout << ans << endl;
}
}else{
cout << "escaped" << endl;
}
}
}
signed main(){
// freopen("" , "r" , stdin);
// freopen("" , "w" , stdout);
// cout << setprecision(30);
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int ts = 1;
// cin >> ts;
while(ts--){
solve();
}
}
