#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pii pair <int, int>
#define fi first
#define se second
#define mp make_pair
const int NM = 1e5, SZ = 320, INF = 1e18+7;
struct edge{
int par, son;
};
int N, S, Q, E;
vector <pii> adj[NM+5];
edge e[NM+5];
int A[NM+5], is_shop[NM+5];
int parent[NM+5], h[NM+5], dist[NM+5], shopNum[NM+5], lg2[NM+5];
int P[NM+5][20];
pii banned_edge;
void DFS(int u){
if (is_shop[u]) shopNum[u] = 1;
for (int i = 0; i < adj[u].size(); i++){
int v = adj[u][i].fi;
if (h[v] == -1){
parent[v] = u;
h[v] = h[u]+1;
dist[v] = dist[u]+adj[u][i].se;
DFS(v);
shopNum[u] += shopNum[v];
}
}
}
void build(){
for (int i = 1; i <= N; i++)
P[i][0] = parent[i];
for (int j = 1; j <= lg2[N]; j++)
for (int i = 1; i <= N; i++)
if (P[i][j-1] != -1) P[i][j] = P[P[i][j-1]][j-1];
else P[i][j] = -1;
}
void preprocess(){
parent[1] = -1, h[1] = 0, dist[1] = 0;
for (int i = 2; i <= N; i++)
h[i] = -1;
DFS(1);
for (int i = 1; i < N; i++)
if (parent[e[i].par] == e[i].son) swap(e[i].par, e[i].son);
lg2[1] = 0;
for (int i = 2; i <= N; i++)
lg2[i] = lg2[i>>1]+1;
build();
}
int binlift(int u, int k){
for (int i = lg2[k]; i >= 0; i--)
if ((k&(1<<i)) != 0) u = P[u][i];
return u;
}
int LCA(int u, int v){
if (h[u] < h[v]) swap(u, v);
u = binlift(u, h[u]-h[v]);
if (u == v) return u;
for (int i = lg2[h[u]]; i >= 0; i--)
if (P[u][i] != -1 && P[u][i] != P[v][i]){
u = P[u][i];
v = P[v][i];
}
return parent[u];
}
int Find(int u){
if (is_shop[u]) return 0;
int res = +INF;
for (int i = 0; i < adj[u].size(); i++){
int v = adj[u][i].fi;
if (mp(u, v) == banned_edge || mp(v, u) == banned_edge) continue;
res = min(res, Find(v)+adj[u][i].se);
}
return res;
}
bool is_ancestor(int a, int u){
if (h[a] > h[u]) return 0;
return binlift(u, h[u]-h[a]) == a;
}
int D(int u, int v){
int a = LCA(u, v);
return dist[u]+dist[v]-2*dist[a];
}
void solve(){
while (Q--){
int I, R;
cin >> I >> R;
int v = e[I].son, ans = +INF;
if (is_ancestor(v, R)){
if (is_ancestor(v, E)){
cout << "escaped\n"; continue;
}
if (shopNum[v] == 0){
cout << "oo\n"; continue;
}
if (S <= SZ){
for (int i = 1; i <= S; i++)
if (is_ancestor(v, A[i])) ans = min(ans, D(R, A[i]));
}
else{
banned_edge = mp(e[I].par, e[I].son);
ans = Find(R);
}
}
else{
if (!is_ancestor(v, E)){
cout << "escaped\n"; continue;
}
if (shopNum[v] == S){
cout << "oo\n"; continue;
}
for (int i = 1; i <= S; i++)
if (!is_ancestor(v, A[i])) ans = min(ans, D(R, A[i]));
else{
banned_edge = mp(e[I].par, e[I].son);
ans = Find(R);
}
}
cout << ans << "\n";
}
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> N >> S >> Q >> E;
for (int i = 1; i < N; i++){
int A, B, W;
cin >> A >> B >> W;
adj[A].push_back(mp(B, W));
adj[B].push_back(mp(A, W));
e[i].par = A, e[i].son = B;
}
for (int i = 1; i <= S; i++){
cin >> A[i];
is_shop[A[i]] = 1;
}
preprocess();
solve();
return 0;
}
