#include <iostream>
#include <vector>
#include <tuple>
#include <queue>
#include <stack>
#include <deque>
#include <set>
#include <map>
#include <cmath>
#include <random>
#include <string>
#include <cassert>
#include <climits>
#include <algorithm>
#include <unordered_set>
#include <unordered_map>
using namespace std;
#define ll long long
#define f first
#define s second
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template<typename A> void __print(const A &x);
template<typename A, typename B> void __print(const pair<A, B> &p);
template<typename... A> void __print(const tuple<A...> &t);
template<typename T> void __print(stack<T> s);
template<typename T> void __print(queue<T> q);
template<typename T, typename... U> void __print(priority_queue<T, U...> q);
template<typename A> void __print(const A &x) {
bool first = true;
cerr << '{';
for (const auto &i : x) {
cerr << (first ? "" : ","), __print(i);
first = false;
}
cerr << '}';
}
template<typename A, typename B> void __print(const pair<A, B> &p) {
cerr << '(';
__print(p.f);
cerr << ',';
__print(p.s);
cerr << ')';
}
template<typename... A> void __print(const tuple<A...> &t) {
bool first = true;
cerr << '(';
apply([&first] (const auto &...args) { ((cerr << (first ? "" : ","), __print(args), first = false), ...); }, t);
cerr << ')';
}
template<typename T> void __print(stack<T> s) {
vector<T> debugVector;
while (!s.empty()) {
T t = s.top();
debugVector.push_back(t);
s.pop();
}
reverse(debugVector.begin(), debugVector.end());
__print(debugVector);
}
template<typename T> void __print(queue<T> q) {
vector<T> debugVector;
while (!q.empty()) {
T t = q.front();
debugVector.push_back(t);
q.pop();
}
__print(debugVector);
}
template<typename T, typename... U> void __print(priority_queue<T, U...> q) {
vector<T> debugVector;
while (!q.empty()) {
T t = q.top();
debugVector.push_back(t);
q.pop();
}
__print(debugVector);
}
void _print() { cerr << "]\n"; }
template <typename Head, typename... Tail> void _print(const Head &H, const Tail &...T) {
__print(H);
if (sizeof...(T)) cerr << ", ";
_print(T...);
}
#ifdef DEBUG
#define D(...) cerr << "Line: " << __LINE__ << " [" << #__VA_ARGS__ << "] = ["; _print(__VA_ARGS__)
#else
#define D(...)
#endif
int n, s, q, e, k, r, hgr, lwr, st, idx, in[100005], out[100005], depth[100005], par[100005][20];
ll dist[100005], val[100005][20], ans;
vector<pair<int, int>> edges, adj[100005];
bool shop[100005];
void dfs1(int curr, int p) {
in[curr] = idx++;
for (auto [i, d] : adj[curr]) {
if (i == p) continue;
depth[i] = depth[curr] + 1;
dist[i] = dist[curr] + d;
par[i][0] = curr;
dfs1(i, curr);
}
out[curr] = idx++;
}
void dfs2(int curr, int p) {
for (auto [i, d] : adj[curr]) {
if (i == p) continue;
dfs2(i, curr);
}
if (shop[curr]) val[curr][0] = dist[curr];
else val[curr][0] = 1e18;
for (auto [i, d] : adj[curr]) {
val[curr][0] = min(val[curr][0], val[i][0]);
}
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cin >> n >> s >> q >> e;
for (int i = 0, a, b, w; i < n - 1; i++) {
cin >> a >> b >> w;
adj[a].push_back({b, w});
adj[b].push_back({a, w});
edges.push_back({a, b});
}
for (int i = 0, x; i < s; i++) {
cin >> x;
shop[x] = true;
}
dfs1(e, -1);
fill(&val[0][0], &val[0][0] + sizeof(val) / sizeof(val[0][0]), 1e18);
dfs2(e, -1);
for (int i = 1; i <= n; i++) {
val[i][0] = val[i][0] - 2 * dist[i];
}
for (int i = 1; i < 20; i++) {
for (int j = 1; j <= n; j++) {
par[j][i] = par[par[j][i - 1]][i - 1];
val[j][i] = min(val[j][i - 1], val[par[j][i - 1]][i - 1]);
}
}
while (q--) {
cin >> k >> r;
hgr = edges[k - 1].f;
lwr = edges[k - 1].s;
if (depth[hgr] > depth[lwr]) swap(hgr, lwr);
if (!(in[lwr] <= in[r] && out[r] <= out[lwr])) {
cout << "escaped\n";
continue;
}
ans = 1e18, st = r;
for (int i = 19; i >= 0; i--) {
if (depth[r] - depth[lwr] >= 1 << i) {
ans = min(ans, val[r][i]);
r = par[r][i];
}
}
ans = min(ans, val[lwr][0]);
if (ans == 1e18) cout << "oo\n";
else cout << dist[st] + ans << "\n";
}
}
