#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
const int N = 100000;
const i64 inf = 1e18;
int n, s, q, E, t = 0;
vector<i64> in(N), out(N), shop(N), x(N, inf), dp(N), d(N);
vector<pair<int, int>> e;
vector<vector<pair<int, int>>> g(N);
vector<vector<i64>> go(N, vector<i64>(18)), mn(N, vector<i64>(18));
void dfs(int u, int p) {
in[u] = t++;
go[u][0] = p;
if (shop[u]) {
x[u] = d[u];
}
for (auto [v, w] : g[u]) {
if (v != p) {
d[v] = d[u] + w;
dfs(v, u);
x[u] = min(x[u], x[v]);
}
}
dp[u] = (x[u] == inf ? inf : x[u] - 2 * d[u]);
mn[u][0] = dp[u];
out[u] = t++;
}
bool is_ancestor(int u, int v) {
return (in[u] <= in[v] && out[u] >= out[v]);
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
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++) {
go[i][b] = go[go[i][b - 1]][b - 1];
mn[i][b] = min(mn[i][b - 1], mn[go[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 {
i64 best = dp[u], dd = d[r];
for (int b = 17; b >= 0; b--) {
if (is_ancestor(u, go[r][b])) {
best = min(best, mn[r][b]);
r = go[r][b];
}
}
if (best == inf) {
cout << "oo\n";
} else {
cout << dd + best << '\n';
}
}
}
}
