#include <bits/stdc++.h>
#define FOR(i, x, y) for (int i = x; i < y; i++)
#define MOD 1000000007
typedef long long ll;
using namespace std;
pair<int, int> roads[100000];
vector<pair<int, int>> graph[100001];
bool is_shop[100001];
int tin[100001], tout[100001], level[100001], indx = 0;
pair<int, ll> bl[100001][20]; // Binary Lifting
ll dp1[100001], dp2[100001][20];
void dfs(int node, int parent = 0, int depth = 0) {
tin[node] = indx++;
level[node] = depth;
dp1[node] = (is_shop[node] ? 0 : 1ll << 60);
FOR(i, 1, 20) {
bl[node][i] = {
bl[bl[node][i - 1].first][i - 1].first,
bl[node][i - 1].second + bl[bl[node][i - 1].first][i - 1].second};
}
for (auto& i : graph[node]) {
if (i.first != parent) {
bl[i.first][0] = {node, i.second};
dfs(i.first, node, depth + 1);
dp1[node] = min(dp1[node], dp1[i.first] + i.second);
}
}
tout[node] = indx++;
}
void dfs2(int node, int parent = 0, int dist = 0) {
dp2[node][0] = dp1[parent] + dist;
FOR(i, 1, 20) {
dp2[node][i] = min(dp2[node][i - 1], dp2[bl[node][i - 1].first][i - 1] +
bl[node][i - 1].second);
}
for (auto& i : graph[node]) {
if (i.first != parent) dfs2(i.first, node, i.second);
}
}
bool is_ancestor(int u, int v) {
return (tin[u] >= tin[v] && tout[u] <= tout[v]);
}
int main() {
iostream::sync_with_stdio(false);
cin.tie(0);
int n, s, q, e;
cin >> n >> s >> q >> e;
FOR(i, 1, n) {
int a, b, w;
cin >> a >> b >> w;
graph[a].push_back({b, w});
graph[b].push_back({a, w});
roads[i] = {a, b};
}
FOR(i, 0, s) {
int x;
cin >> x;
is_shop[x] = true;
}
dfs(e);
dfs2(e);
while (q--) {
int i, r;
cin >> i >> r;
if (is_ancestor(r, roads[i].first) && is_ancestor(r, roads[i].second)) {
if (tin[roads[i].first] < tin[roads[i].second])
swap(roads[i].first, roads[i].second);
int dist = level[r] - level[roads[i].first];
ll ans = dp1[r];
ll len = 0;
int pw = 0;
while (dist) {
if (dist & 1) {
ans = min(ans, len + dp2[r][pw]);
len += bl[r][pw].second;
r = bl[r][pw].first;
}
dist >>= 1;
pw++;
}
if (ans == 1ll << 60)
cout << "oo\n";
else
cout << ans << '\n';
} else
cout << "escaped\n";
}
return 0;
}
