#include <bits/stdc++.h>
#pragma GCC target("avx2")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
using namespace std;
#define ii pair<int , int>
#define iv pair<ii , ii>
#define iii pair<int , ii>
#define fi first
#define se second
#define int long long
const int inf = 1e18 + 7;
const int MAX_N = 1e5 + 7;
const int MOD = 1e9 + 7;
int ti[MAX_N] , to[MAX_N];
vector<ii> adj[MAX_N];
int H[MAX_N];
int P[MAX_N][19];
int C[MAX_N][19];
int f[MAX_N];
int g[MAX_N];
int d[MAX_N];
int vis[MAX_N];
int check[MAX_N];
int timeDFS = 0;
int n , s , q , e;
vector<ii> seg;
void DFS(int u , int father) {
P[u][0] = father;
ti[u] = ++timeDFS;
for (auto edge : adj[u]) {
int v , w; tie(v , w) = edge;
if (v != father) {
H[v] = H[u] + 1;
d[v] = d[u] + w;
DFS(v , u);
}
}
to[u] = ++timeDFS;
}
void DFS1(int u , int father) {
if (check[u]) g[u] = d[u];
for (auto edge : adj[u]) {
int v , w; tie(v , w) = edge;
if (v != father) {
DFS1(v , u);
g[u] = min(g[u] , g[v]);
}
}
}
void DFS2(int u , int father) {
if (father != -1) {
C[u][0] = f[father];
}
for (auto edge : adj[u]) {
int v , w; tie(v , w) = edge;
if (v != father) {
DFS2(v , u);
}
}
}
void buildtable() {
for (int u = 1 ; u <= n ; u++) {
for (int k = 1 ; k < 19 ; k ++) {
P[u][k] = -1;
C[u][k] = inf;
}
}
for (int k = 1 ; k < 19 ;k++) {
for (int u = 1 ; u <= n ; u++) {
if (P[u][k - 1] != -1){
P[u][k] = P[P[u][k - 1]][k - 1];
C[u][k] = min(C[u][k - 1] , C[P[u][k - 1]][k - 1]);
}
}
}
}
int LCA(int u , int v) {
if (H[u] < H[v]) {
swap(u , v);
}
int ans = inf;
while (H[u] > H[v]) {
for (int k = 18 ; k >= 0 ; k --) {
if (P[u][k] != -1 && H[P[u][k]] >= H[v]) {
ans = min(ans , C[u][k]);
u = P[u][k];
break;
}
}
}
if (u == v) return ans;
while (true) {
bool found = false;
for (int k = 18 ; k >= 0 ; k --) {
if (P[u][k] != 1 && P[v][k] != -1 && P[u][k] != P[v][k]) {
ans = min({ans , C[u][k] , C[v][k]});
u = P[u][k];
v = P[v][k];
found = true;
break;
}
}
if (!found) {
break;
}
}
ans = min({ans , C[u][0] , C[v][0]});
return ans;
}
signed main() {
ios_base::sync_with_stdio(0); cin.tie(NULL); cout.tie(NULL);
cin >> n >> s >> q >> e;
for (int i = 1 ; i < n ; i++) {
int u , v , w; cin >> u >> v >> w;
adj[u].push_back(ii(v , w));
adj[v].push_back(ii(u , w));
seg.push_back(ii(u , v));
}
for (int i = 1 ; i <= n ; i++) {
g[i] = inf;
}
for (int i = 1 ; i <= s ; i++) {
int x; cin >> x;
check[x] = true;
}
C[e][0] = inf;
DFS(e , -1);
DFS1(e , -1);
for (int i = 1 ; i <= n ; i++) {
if (g[i] != inf)
f[i] = -2*d[i] + g[i];
else f[i] = inf;
}
DFS2(e , -1);
buildtable();
for (int i = 1 ; i <= q ; i++) {
int I , R; cin >> I >> R;
int u , v; tie(u , v) = seg[I - 1];
if (H[u] < H[v]) swap(u , v);
if(ti[u] <= ti[R] && to[R] <= to[u]) {
int x = LCA(u , R);
if (x == inf) {
cout << "oo" << '\n';
}
else cout << min(d[R] + x , d[R] + f[R]) << '\n';
}
else {
cout << "escaped" << '\n';
}
}
return 0;
}
