// #include <bits/stdc++.h>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <map>
#include <vector>
#include <iomanip>
#include <string>
#include <queue>
#include <set>
#include <deque>
#include <numeric>
#include <stack>
#include <chrono>
using namespace std;
void fast_io() {
// freopen("", "r", stdin);
// freopen("", "w", stdout);
ios::sync_with_stdio(0);
cin.tie();
cout.tie();
cout << setprecision(9);
}
#define int long long
#define endl '\n'
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define fi first
#define se second
const int N = 1e5 + 5, L = 17;
vector<pair<int, int>> adj[N];
bool V[N];
vector<int> ord;
int dist[N], dpth[N], Shop[N], par[N], sp[N][L], mi[N][L], magic[N];
int St[N], En[N], Time;
void sp_table(int u){
sp[u][0] = par[u];
mi[u][0] = magic[u];
int power = 1;
for (int i = 1; i < 17; i++){
power *= 2;
if (dpth[u] < power){
sp[u][i] = 0;
mi[u][i] = 1e18;
}
else {
sp[u][i] = sp[sp[u][i - 1]][i - 1];
mi[u][i] = min(mi[u][i - 1], mi[sp[u][i - 1]][i - 1]);
}
}
}
void dfs(int u){
St[u] = ++Time;
ord.push_back(u);
Shop[u] = (V[u] ? dist[u] : (int)1e18);
for (auto [v, w] : adj[u]){
if (v == par[u]) continue;
par[v] = u;
dist[v] = dist[u] + w;
dpth[v] = dpth[u] + 1;
dfs(v);
Shop[u] = min(Shop[u], Shop[v]);
}
En[u] = Time;
magic[u] = Shop[u] - 2 * dist[u];
}
void solve() {
int n, s, q, e;
cin >> n >> s >> q >> e;
vector<pair<int, int>> E = {{0, 0}};
for (int i = 1; i < n; i++){
int u, v, w; cin >> u >> v >> w;
adj[u].push_back({v, w});
adj[v].push_back({u, w});
E.push_back({u, v});
}
for (int i = 1; i <= s; i++){
int CC; cin >> CC;
V[CC] = 1;
}
dfs(e);
for (auto i : ord){
sp_table(i);
}
for (int Q = 1; Q <= q; Q++){
int I, R; cin >> I >> R;
int u = E[I].fi, v = E[I].se;
int p = (par[v] == u ? v : u);
if (!(St[p] <= St[R] && St[R] <= En[p])){
cout << "escaped" << endl;
continue;
}
else if (Shop[p] >= 1e18){
cout << "oo" << endl;
continue;
}
int diff = dpth[R] - dpth[p];
int ans = 1e18;
int po = 0;
int cur = R;
while (diff > 0){
if (diff & 1){
ans = min(ans, mi[cur][po]);
cur = sp[cur][po];
}
po++;
diff >>= 1;
}
ans = min(ans, magic[p]);
cout << ans + dist[R] << endl;
}
}
signed main() {
fast_io();
srand(chrono::steady_clock::now().time_since_epoch().count());
int tc = 1;
// cin >> tc;
while (tc--) solve();
return 0;
}
