#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int nmax = 1e5 + 5, lg = 17;
const ll inf = 1e17;
int n, s, q, e, up[nmax][20], in[nmax], out[nmax], timer;
ll d[nmax], mn[nmax][20], dp[nmax];
vector <pair <int, ll>> g[nmax];
bool shop[nmax];
pair <int, int> road[nmax];
void dfs(int u) {
dp[u] = inf;
if (shop[u]) dp[u] = 0;
in[u] = ++timer;
for (auto [v, w] : g[u]) {
if (v==up[u][0]) continue;
d[v] = d[u] + w;
up[v][0] = u;
dfs(v);
dp[u] = min(dp[u], w + dp[v]);
}
mn[u][0] = dp[u] - d[u];
out[u] = timer;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cin >> n >> s >> q >> e;
for (int i=1; i<n; i++) {
int u, v; ll w;
cin >> u >> v >> w;
g[u].push_back({v, w});
g[v].push_back({u, w});
road[i] = {u, v};
}
while (s--) {
int u; cin >> u;
shop[u] = true;
}
dfs(e);
for (int j=1; j<=lg; j++) {
for (int i=1; i<=n; i++) {
up[i][j] = up[up[i][j - 1]][j - 1];
mn[i][j] = min(mn[i][j - 1], mn[up[i][j - 1]][j - 1]);
}
}
while (q--) {
int i, r; cin >> i >> r;
auto [u, v] = road[i];
if (d[u]<d[v]) swap(u, v);
if (in[u]<=in[r] && in[r]<=out[u]) {
ll ans = inf;
int cur = r;
for (int j=lg; j>=0; j--) {
if (d[up[cur][j]]>=d[u]) {
ans = min(ans, mn[cur][j]);
cur = up[cur][j];
}
}
ans = min(ans, mn[cur][0]);
if (ans>=1e14) cout << "oo\n";
else cout << d[r] + ans << '\n';
}
else cout << "escaped\n";
}
return 0;
}
