#include <iostream>
#include <vector>
#include <map>
using namespace std;
#define F0R(i, n) for (ll i = 0; i < n;i++)
#define FOR(i, j , n) for (ll i = j ; i< n;i++)
using ll = long long;
template<typename T>
using V = vector<T>;
using vi = V<ll>;
using pi = pair<ll,ll>;
constexpr ll INF = 1e16 + 7;
struct Seg {
Seg *left = nullptr, *right = nullptr;
ll l, r, mid;
ll v = INF, lazy = 0;
Seg(ll l, ll r) : l(l), r(r), mid((l + r) / 2) {
if (r -l > 1) {
left = new Seg(l, mid), right = new Seg(mid, r);
}
}
void push() {
if (lazy == 0) return;
if (r - l > 1) {
left->lazy += lazy; right->lazy += lazy;
}
v += lazy;
lazy = 0;
}
ll q(ll a, ll b) {
push();
if (b <= l || a >= r) return INF;
if (a <= l && b >= r) return v;
return min(left->q(a,b), right->q(a,b));
}
void pollUpdate(ll x, ll u) {
push();
if (r - l <= 1) {
v = u;
return;
}
if (x < mid)
left->pollUpdate(x, u);
else
right->pollUpdate(x, u);
left->push();
right->push();
v = min(left->v, right->v);
}
void update(ll a, ll b, ll u) {
push();
if (b <= l || a >= r) return;
if (a <= l && b >= r) {
lazy += u;
push();
return;
}
left->update(a,b, u); right->update(a,b,u);
v = min(left->v, right->v);
}
};
V<V<pi>> queries; // Node -> index of edge, index of query
vi ans;
V<V<tuple<ll, ll, ll>>> g; // y, index, w
V<ll> dp;
V<bool> spec;
void computeDp(ll x, ll p) {
if (spec[x]) dp[x] = 0;
for (auto [y, i, w] : g[x]) {
if (y == p) continue;
computeDp(y, x);
dp[x] = min(dp[x], dp[y] + w);
}
}
vi updates;
Seg* seg;
void dfs(ll x, ll p, map<ll, ll> &path, ll d = 0) {
for (auto [edge, i] : queries[x]) {
if (!path.count(edge)) {
ans[i] = -1; continue;
}
ans[i] = seg->q(path[edge], 1e9);
}
for (auto [y, i, w] : g[x]) {
if (y == p) continue;
path[i] = d + 1;
seg->update(0,1e9, w);
seg->pollUpdate(d + 1, dp[y]);
dfs(y, x, path, d + 1);
seg->pollUpdate(d + 1, INF);
seg->update(0,1e9, -w);
path.erase(i);
}
}
int main() {
ll n, s, q, e; cin >> n >> s >> q >> e;
g.resize(n + 1);
spec.resize(n + 1);
dp.resize(n + 1, INF);
queries.resize(n + 1);
ans.resize(q);
F0R(i, n - 1) {
ll a, b, c; cin >> a >> b >> c;
g[a].emplace_back(b, i, c);
g[b].emplace_back(a, i, c);
}
F0R(i, s) {
ll x; cin >> x;
spec[x] = 1;
}
F0R(i, q) {
ll edge, node; cin >> edge >> node; edge--;
queries[node].emplace_back(edge, i);
}
computeDp(e, -1);
map<ll, ll> m;
seg = new Seg(0, n + 1);
dfs(e, -1, m);
F0R(i, q) {
if (ans[i] == -1) {
cout << "escaped\n";
}
else if (ans[i] >= INF / 2)
cout << "oo\n";
else cout << ans[i] << "\n";
}
}
