#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif
const int N = 1e5 + 5;
const long long inf = 1e18;
int n, k, q, r;
int L[N], R[N], w[N], ver[N];
bool shop[N];
long long dep[N], res[N], c[4 * N], s[4 * N];
vector<array<int, 2>> g[N], que[N];
void upd(int u, int v, long long x, int id = 1, int l = 1, int r = n) {
if (u <= l && r <= v) {
c[id] += x;
s[id] += x;
return;
}
int m = (l + r) / 2;
if (u <= m) {
upd(u, v, x, id * 2, l, m);
}
if (m < v) {
upd(u, v, x, id * 2 + 1, m + 1, r);
}
s[id] = min(s[id * 2], s[id * 2 + 1]) + c[id];
}
int timer;
void dfs(int u) {
L[u] = ++timer;
for (auto [v, id] : g[u]) {
if (!L[v]) {
ver[id] = v;
dep[v] = dep[u] + w[id];
dfs(v);
}
}
R[u] = timer;
}
void add(int u, long long x) {
if (1 < L[u]) {
upd(1, L[u] - 1, x);
}
if (R[u] < n) {
upd(R[u] + 1, n, x);
}
}
void solve(int u) {
for (auto [p, id] : que[u]) {
if (L[p] <= L[u] && L[u] <= R[p]) {
add(p, inf);
res[id] = s[1] < inf ? s[1] : -2;
add(p, -inf);
} else {
res[id] = -1;
}
}
for (auto [v, id] : g[u]) {
if (L[v] > L[u]) {
upd(L[v], R[v], -w[id]);
add(v, w[id]);
solve(v);
upd(L[v], R[v], w[id]);
add(v, -w[id]);
}
}
}
int main() {
ios::sync_with_stdio(false); cin.tie(nullptr);
cin >> n >> k >> q >> r;
for (int i = 1; i < n; ++i) {
int u, v; cin >> u >> v >> w[i];
g[u].push_back({v, i});
g[v].push_back({u, i});
}
dfs(r);
while (k--) {
int u; cin >> u;
shop[u] = 1;
}
for (int i = 1; i <= n; ++i) {
upd(L[i], L[i], dep[i] + (shop[i] ? 0 : inf));
}
for (int i = 1; i <= q; ++i) {
int id, r; cin >> id >> r;
que[r].push_back({ver[id], i});
}
solve(r);
for (int i = 1; i <= q; ++i) {
if (res[i] == -2) {
cout << "oo" << "\n";
} else if (res[i] == -1) {
cout << "escaped" << "\n";
} else {
cout << res[i] << "\n";
}
}
return 0;
}
