#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vl = vector<ll>;
const int MOD = 1e9+7;
#define F first
#define S second
#define PB push_back
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
void FASTIO() {ios::sync_with_stdio(0); cin.tie(0); cout.tie(0); }
const int MXN = 1e5+5;
const int MXK = 16;
const ll INF = 1e15;
int n, s, q, e;
vector<tuple<int, int, ll>> E = {{}};
vector<pil> adj[MXN];
bool shop[MXN];
int BL[MXK][MXN];
ll BL_w[MXK][MXN];
ll BL_dp[MXK][MXN];
int H[MXN];
ll dp[MXN];
void dfs(int u, int p) {
dp[u] = (shop[u] ? 0 : INF);
for(auto edge : adj[u]) {
int v = edge.F;
if(v == p) continue;
BL[0][v] = u;
BL_w[0][v] = edge.S;
H[v] = H[u]+1;
dfs(v, u);
dp[u] = min(dp[u], dp[v]+edge.S); // dp going down the subtree
}
}
int main() {
FASTIO();
cin >> n >> s >> q >> e;
for(int i = 0; i < n-1; i++) {
int a, b, w; cin >> a >> b >> w;
E.PB({a, b, w});
adj[a].PB({b, w});
adj[b].PB({a, w});
}
for(int i = 0; i < s; i++) {
int j; cin >> j; shop[j] = true;
}
dfs(e, -1);
BL[0][e] = e;
for(int i = 1; i <= n; i++) {
BL_dp[0][i] = min(dp[i], dp[BL[0][i]]+BL_w[0][i]);
}
for(int k = 1; k < MXK; k++) {
for(int i = 1; i <= n; i++) {
BL[k][i] = BL[k-1][BL[k-1][i]];
BL_w[k][i] = BL_w[k-1][i]+BL_w[k-1][BL[k-1][i]];
BL_dp[k][i] = min(BL_dp[k-1][i], BL_dp[k-1][BL[k-1][i]]+BL_w[k-1][i]);
}
}
for(int qq = 0; qq < q; qq++) {
int i, r; cin >> i >> r;
// 1. binary lift to check if i-th edge is the one needed to take to reach the root
// 2. if yes, check dp for minimal distance to shop(?)
int u = H[get<0>(E[i])] > H[get<1>(E[i])] ? get<0>(E[i]) : get<1>(E[i]);
if(H[r] < H[u]) {
cout << "escaped\n";
continue;
}
int v = r;
ll ans = INF;
ll curr = 0;
for(int k = MXK-1; k >= 0; k--)
while(H[BL[k][v]] >= H[u]) {
ans = min(ans, BL_dp[k][v]+curr);
curr += BL_w[k][v];
v = BL[k][v];
}
if(u != v) {
cout << "escaped\n";
continue;
}
if(ans >= INF) {
cout << "oo\n";
}
else {
cout << ans << "\n";
}
}
return 0;
}
/*
*/
