#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 100000;
const int OO = 1e18;
int n, s, q, E, t = 0;
vector<int> inTime(N), outTime(N), shop(N), shopDistanceToE(N, OO), distanceToShop(N), distanceToE(N);
vector<pair<int, int>> e;
vector<vector<pair<int, int>>> g(N);
vector<vector<int>> binaryJumpVertex(N, vector<int>(18)), mn(N, vector<int>(18));
void dfs(int u, int p) {
inTime[u] = t++;
binaryJumpVertex[u][0] = p;
if (shop[u]) {
shopDistanceToE[u] = distanceToE[u];
}
for (auto [v, w] : g[u]) {
if (v != p) {
distanceToE[v] = distanceToE[u] + w;
dfs(v, u);
shopDistanceToE[u] = min(shopDistanceToE[u], shopDistanceToE[v]);
}
}
distanceToShop[u] = (shopDistanceToE[u] == OO ? OO : shopDistanceToE[u] - 2 * distanceToE[u]);
mn[u][0] = distanceToShop[u];
outTime[u] = t++;
}
bool is_ancestor(int u, int v) {
return (inTime[u] <= inTime[v] && outTime[v] <= outTime[u]);
}
signed main() {
cin >> n >> s >> q >> E;
--E;
for (int i = 0; i < n - 1; i++) {
int u, v, w;
cin >> u >> v >> w;
--u;
--v;
e.emplace_back(u, v);
g[u].emplace_back(v, w);
g[v].emplace_back(u, w);
}
for (int i = 0; i < s; i++) {
int u;
cin >> u;
shop[u - 1] = 1;
}
dfs(E, E);
for (int b = 1; b < 18; b++) {
for (int i = 0; i < n; i++) {
binaryJumpVertex[i][b] = binaryJumpVertex[binaryJumpVertex[i][b - 1]][b - 1];
mn[i][b] = min(mn[i][b - 1], mn[binaryJumpVertex[i][b - 1]][b - 1]);
}
}
while (q--) {
int i, r;
cin >> i >> r;
--i; --r;
auto [u, v] = e[i];
if (is_ancestor(u, v)) {
swap(u, v);
}
if (!is_ancestor(u, r)) {
cout << "escaped\n";
} else {
int best = distanceToShop[u], distanceRE = distanceToE[r];
for (int b = 17; b >= 0; b--) {
if (is_ancestor(u, binaryJumpVertex[r][b])) {
best = min(best, mn[r][b]);
r = binaryJumpVertex[r][b];
}
}
if (best == OO) {
cout << "oo\n";
} else {
cout << distanceRE + best << '\n';
}
}
}
}
