#include <bits/stdc++.h>
const int N = 1e5 + 5;
const int L = 18;
int n, s, q, e;
std::vector<std::pair<int, int>> gr[N];
int dep[N], anc[L][N], f[L][N], spec[N], sub[N];
int tin[N], tout[N], tt = 0;
void dfs(int u, int p = 0) {
tin[u] = ++tt;
anc[0][u] = p;
for (auto [v, c] : gr[u]) {
if (v != p) {
dep[v] = dep[u] + c;
dfs(v, u);
}
}
tout[u] = tt;
}
bool is_ancestor(int a, int b) {
return tin[a] <= tin[b] && tout[b] <= tout[a];
}
void build(int u, int p = 0) {
sub[u] = 1e9;
if (spec[u] == 1) {
sub[u] = dep[u];
}
for (auto [v, c] : gr[u]) {
if (v != p) {
build(v, u);
sub[u] = std::min(sub[u], sub[v]);
}
}
}
int get_min(int a, int b) {
int mn = 1e9;
for (int h = L - 1; h >= 0; h--) {
if (dep[a] - (1 << h) >= dep[b]) {
mn = std::min(mn, f[h][a]);
a = anc[h][a];
}
}
return mn;
}
int main() {
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr);
std::cin >> n >> s >> q >> e;
std::vector<std::pair<int, int>> edges(n);
for (int i = 1; i < n; i++) {
int a, b, w;
std::cin >> a >> b >> w;
gr[a].push_back({b, w});
gr[b].push_back({a, w});
edges[i] = {a, b};
}
dfs(e);
for (int h = 1; h < L; h++) {
for (int i = 1; i <= n; i++) {
anc[h][i] = anc[h - 1][anc[h - 1][i]];
}
}
for (int i = 1; i < n; i++) {
if (dep[edges[i].first] > dep[edges[i].second]) {
std::swap(edges[i].first, edges[i].second);
}
}
for (int i = 1; i <= s; i++) {
int x;
std::cin >> x;
spec[x] = 1;
}
build(e);
for (int i = 1; i <= n; i++) {
f[0][i] = sub[i] - 2 * dep[i];
}
for (int h = 1; h < L; h++) {
for (int i = 1; i <= n; i++) {
f[h][i] = std::min(f[h - 1][i], f[h - 1][anc[h - 1][i]]);
}
}
while (q--) {
int i, r;
std::cin >> i >> r;
int x = edges[i].second;
if (!is_ancestor(x, r)) {
std::cout << "escaped\n";
continue;
}
if (sub[x] == 1e9) {
std::cout << "oo\n";
continue;
}
std::cout << dep[r] + get_min(r, edges[i].first) << "\n";
}
return 0;
}
