#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define all(aaa) aaa.begin(), aaa.end()
struct E {
int to, w;
};
const int N = 1e5 + 5;
vector<E> g[N];
vector<int>qr[N];
int hurdle[N], tin[N], tout[N], x[N], tour[N];
ll h[N], up[N * 4];
pair<int, ll> t[N * 4], ans[N];
bool isShop[N];
vector<pair<int, int>> edges;
int n, s, q, e, timer = -1;
void push(int v, int L, int R) {
if (up[v]) {
t[v].second += up[v];
if (L != R) {
up[v * 2] += up[v];
up[v * 2 + 1] += up[v];
}
up[v] = 0;
}
}
void build(int v = 1, int L = 0, int R = n - 1) {
if (L == R) {
if (tour[L] == e) {
t[v] = { -1, 0 };
}
else if (isShop[tour[L]]) {
t[v] = { 0, h[tour[L]] };
}
else {
t[v] = { 1, 0 };
}
}
else {
int m = (L + R) >> 1;
build(v * 2, L, m);
build(v * 2 + 1, m + 1, R);
t[v] = min(t[v * 2], t[v * 2 + 1]);
}
}
void upd(int l, int r, ll x, int v = 1, int L = 0, int R = n - 1) {
push(v, L, R);
if (l > r)
return;
if (l == L && r == R) {
up[v] += x;
push(v, L, R);
}
else {
int m = (L + R) >> 1;
upd(l, min(m, r), x, v * 2, L, m);
upd(max(m + 1, l), r, x, v * 2 + 1, m + 1, R);
t[v] = min(t[v * 2], t[v * 2 + 1]);
}
}
pair<int, ll> que(int l, int r, int v = 1, int L = 0, int R = n - 1) {
push(v, L, R);
if (l > r)
return { 1, 0 };
if (l == L && r == R) {
return t[v];
}
int m = (L + R) >> 1;
return min(que(l, min(m, r), v * 2, L, m),
que(max(m + 1, l), r, v * 2 + 1, m + 1, R));
}
void dfs(int node, int anc) {
tin[node] = ++timer;
tour[timer] = node;
for (E e : g[node]) {
if (e.to != anc) {
h[e.to] = h[node] + e.w;
dfs(e.to, node);
}
}
tout[node] = timer;
}
bool upper(int a, int b) {
return tin[a] <= tin[b] && tout[a] >= tout[b];
}
void deep(int node, int anc) {
for (int i : qr[node]) {
if (upper(hurdle[i], node)) {
ans[i] = que(tin[hurdle[i]], tout[hurdle[i]]);
}
else {
ans[i] = min(que(0, tin[hurdle[i]] - 1), que(tout[hurdle[i]] + 1, n - 1));
}
}
for (E e : g[node]) {
if (e.to != anc) {
upd(0, n - 1, e.w);
upd(tin[e.to], tout[e.to], -2 * e.w);
deep(e.to, node);
upd(0, n - 1, -e.w);
upd(tin[e.to], tout[e.to], 2 * e.w);
}
}
}
signed main() {
#ifdef HOME
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n >> s >> q >> e;
e--;
for (int i = 0; i < n - 1; i++) {
int a, b, w;
cin >> a >> b >> w;
a--, b--;
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;
isShop[x - 1] = 1;
}
dfs(0, -1);
build(1, 0, n - 1);
for (auto &p : edges) {
if (tin[p.first] > tin[p.second])
swap(p.first, p.second);
}
for (int i = 0; i < q; i++) {
int x, y;
cin >> x >> y;
hurdle[i] = edges[x - 1].second;
qr[y - 1].push_back(i);
}
deep(0, -1);
for (int i = 0; i < q; i++) {
if (ans[i].first == -1) {
cout << "escaped";
}
else if (ans[i].first == 0) {
cout << ans[i].second;
}
else {
cout << "oo";
}
cout << "\n";
}
return 0;
}
