#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ff first
#define ss second
#define all(a) a.begin(), a.end()
const int N = 1e5;
const int LOG = 17;
int n, s, q, e;
const int SQRT = 550;
vector< pair<int, int> > g[N + 1];
vector< pair<int, int> > edges;
vector<int> shops;
int is_shop[N+1], up[N+1][LOG+2], depth_sum[N+1];
int depth[N+1], tin[N+1], tout[N+1], range[N+1];
int timer, T;
pair<int, int> euler[N * 2 + 100];
int lg[N*2 + 100];
void dfs(int v, int par){
tin[v] = timer++;
range[v] = T;
euler[T++] = {depth[v], v};
up[v][0] = par;
for(int j = 1;j <= LOG; j++){
up[v][j] = up[up[v][j-1]][j-1];
}
for(auto [to, w] : g[v]){
if(to == par) continue;
depth[to] = depth[v] + 1;
depth_sum[to] = depth_sum[v] + w;
dfs(to, v);
euler[T++] = {depth[v], v};
}
tout[v] = timer;
}
int is_parent(int par, int v){
return (tin[par] <= tin[v] && tout[v] <= tout[par]);
}
pair<int, int> sparse[LOG+3][N * 2+10];
pair<int, int> query_rmq(int a, int b) {
int f = lg[b-a];
return min(sparse[f][a], sparse[f][b - (1<<f)]);
}
int lca(int u, int v) {
return query_rmq(min(range[u], range[v]), max(range[u], range[v]) + 1).ss;
}
int can_reach(int v, int u, int closed){
int LCA = lca(v, u);
if(is_parent(closed, LCA)){
return 1;
}
if(is_parent(closed, v) or is_parent(closed, u)){
return 0;
}
return 1;
}
int distance(int v, int u){
int LCA = lca(v, u);
return depth_sum[v] + depth_sum[u] - 2*depth_sum[LCA];
}
int close(int idx){
return (depth[edges[idx].ff] < depth[edges[idx].ss] ? edges[idx].ss : edges[idx].ff);
}
int mn;
void calc_dist_shop(int v, int par, int closed, int sm){
if(is_shop[v]){
mn = min(mn, sm);
}
set<pair<int, int> > st;
st.insert({0LL, v});
for(auto [to, w] : g[v]){
if(to == edges[closed].ff and v == edges[closed].ss) continue;
if(v == edges[closed].ff and to == edges[closed].ss) continue;
if(to == par) continue;
calc_dist_shop(to, v, closed, sm + w);
}
}
main(){
ios::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
cin >> n >> s >> q >> e;
edges.push_back({-1, -1});
for(int i = 1;i < n; i++){
int a, b, w; cin >> a >> b >> w;
g[a].push_back({b, w});
g[b].push_back({a, w});
edges.push_back({a, b});
}
for(int i = 0;i < s; i++){
int x; cin >> x;
shops.push_back(x);
is_shop[x] = 1;
}
dfs(1, 1);
for(int i = 0;i < T; i++){
sparse[0][i] = euler[i];
}
int logT = 0;
while ((1<<logT) < T) logT++;
for(int f = 0; f < logT; f++){
for(int i = 0;i + (1<<f) < T; i++){
sparse[f+1][i] = min(sparse[f][i], sparse[f][i + (1<<f)]);
}
}
lg[0] = -1;
for(int i = 1;i < T; i++){
lg[i] = lg[i / 2] + 1;
}
while(q--){
int idx, v; cin >> idx >> v;
if(can_reach(v, e, close(idx))){
cout << "escaped";
}else if(s == n){
cout << 0;
}else{
mn = LLONG_MAX;
if(shops.size() > SQRT){
for(int sh : shops){
if(can_reach(v, sh, close(idx)))
mn = min(mn, distance(v, sh));
}
}else{
calc_dist_shop(v, v, idx, 0);
}
if(mn == LLONG_MAX) cout << "oo";
else cout << mn;
}
cout << '\n';
}
return 0;
}
