#include <iostream>
#include <cstdio>
#include <vector>
#include <cmath>
#include <set>
using namespace std;
using ll = long long;
const ll INF = 1e18;
const int MXN = 1e5 + 1;
vector<vector<pair<pair<ll, int>, int>>> adj(MXN, vector<pair<pair<ll, int>, int>>(0));
vector<int> dep(MXN, 0);
vector<ll> diste(MXN, 0);
vector<ll> magic(MXN, INF);
vector<bool> shop(MXN, false);
vector<int> abvdep(MXN);
vector<vector<pair<int, int>>> qatnde(MXN, vector<pair<int, int>>(0));
vector<bool> esc(MXN, false);
vector<ll> fans(MXN, INF);
set<int> edgused;
vector<int> par(MXN, 0);
void dfs(int node, int p = 0)
{
for (pair<int, int> qry : qatnde[node]) if (edgused.count(qry.first) == 0) esc[qry.second] = true;
if (shop[node]) magic[node] = diste[node];
for (int i = 0; i < adj[node].size(); i++)
{
pair<pair<ll, int>, int> nxt = adj[node][i];
if (nxt.first.second != p)
{
edgused.insert(nxt.second), dep[nxt.first.second] = dep[node] + 1, diste[nxt.first.second] = diste[node] + nxt.first.first,
abvdep[nxt.second] = dep[node], par[nxt.first.second] = node;
dfs(nxt.first.second, node);
magic[node] = fmin(magic[node], magic[nxt.first.second]), edgused.erase(nxt.second);
}
}
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, s, q, e;
cin >> n >> s >> q >> e;
for (int i = 1; i < n; i++)
{
int a, b;
ll w;
cin >> a >> b >> w;
adj[a].push_back({ {w, b}, i }), adj[b].push_back({ {w, a}, i });
}
while (s--)
{
int a;
cin >> a;
shop[a] = true;
}
for (int i = 0; i < q; i++)
{
int I, r;
cin >> I >> r;
qatnde[r].push_back({ I, i });
}
dfs(e);
for (int i = 1; i <= n; i++) if (magic[i] != INF) magic[i] -= 2 * diste[i];
vector<vector<int>> blftpar(1, par);
vector<vector<ll>> blftmagic(1, magic);
int k = 18;
while (k--)
{
vector<ll> nmgc = blftmagic.back();
vector<int> npar = blftpar.back();
for (int i = 1; i <= n; i++) npar[i] = blftpar.back()[blftpar.back()[i]], nmgc[i] = fmin(nmgc[i], blftmagic.back()[blftpar.back()[i]]);
blftpar.push_back(npar), blftmagic.push_back(nmgc);
}
for (int node = 1; node <= n; node++) for (pair<int, int> qry : qatnde[node]) if (!esc[qry.second])
{
int cnode = node, goup = dep[node] - abvdep[qry.first];
for (int i = blftpar.size() - 1; i > -1; i--) if (goup & (1 << i))
{
fans[qry.second] = fmin(fans[qry.second], blftmagic[i][cnode]);
cnode = blftpar[i][cnode];
}
if (fans[qry.second] != INF) fans[qry.second] += diste[node];
}
for (int i = 0; i < q; i++)
{
if (esc[i]) cout << "escaped\n";
else if (fans[i] == INF) cout << "oo\n";
else cout << fans[i] << "\n";
}
}
