#include <bits/stdc++.h>
#include <fstream>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
template<class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
struct custom_hash {static uint64_t splitmix64(uint64_t x) {x += 0x9e3779b97f4a7c15;x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;x = (x ^ (x >> 27)) * 0x94d049bb133111eb;return x ^ (x >> 31);}size_t operator()(uint64_t x) const {static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();return splitmix64(x + FIXED_RANDOM);}};
// string __fname = ""; ifstream in (__fname + ".in"); ofstream out (__fname + ".out");
// #define cin in
// #define cout out
#define int64 long long
#define uint64 unsigned long long
#define x first
#define y second
#define pb push_back
#define pii pair <int, int>
#define pii64 pair <int64, int64>
#define db(x) cout << "> " << #x << ": " << (x) << "\n"
#define qr queries()
#define yn(x) if (x) {ctn("Yes");}else {ctn("No");}
void solve(int);
void queries(){int n;cin >> n;for (int i = 1; i <= n; i++) solve(i);}
template<class T>T ceildiv(T a, T b) {return a / b + !!(a % b);}
template<class T>T gcd (T a, T b){return (b ? gcd(b, a % b): a);}
template<class T>T lcm (T a, T b){return a * b / gcd(a, b);}
// // // // // // // // // // // // // // // // // // // // // //
/* TEMPLATE - VANILLA */
// // // // // // // // // // // // // // // // // // // // // //
const int ddx[] = {-1, -1, 0, 1, 1, 1, 0, -1};
const int ddy[] = {0, 1, 1, 1, 0, -1, -1, -1};
const int dx[] = {-1, 0, 1, 0};
const int dy[] = {0, 1, 0, -1};
const double pi = 3.14159265359;
const double eps = 1e-6;
const int64 hash_inv = 940594066;
const int64 hash_p = 101;
const int64 mod = 1e9 + 7;
const int maxn = 1e5 + 2;
const int lg = 20;
vector <pii64> ad [maxn];
vector <pii> eg;
int lca [maxn][lg];
int depth [maxn];
int64 dp [maxn];
int is[maxn];
int n,s,q,r;
void solve(int id){
return;
}
void dfs (int u, int p = -1) {
for (auto [v, c]: ad[u]) {
if (v == p) continue;
depth[v] = depth[u] + 1;
lca[v][0] = u;
for (int i = 1; i < lg; i++) {
lca[v][i] = lca[lca[u][i-1]][i-1];
}
dfs(v, u);
dp[u] = min(dp[u], dp[v] + c);
}
}
// void dfsr(int u, int64 top = 0, int p = -1) {
// vector <int64> el = {(int64) 1e9};
// for (auto [v, c]: ad[u]) {
// if (v == p) continue;
// el.push_back(dp[v]);
// }
// int k = ad[u].size() - 1;
// vector <int64> pref (k + 3, 1e15), suff (k + 3, 1e15);
// for (int i = 1; i <= k; i++){
// pref[i] = min(pref[i-1], el[i]);
// }
// for (int i = k; i >= 1; i--){
// suff[i] = min(suff[i + 1], el[i]);
// }
// dp[u] = min(dp[u], top);
// int idx = 1;
// for (auto [v, c]: ad[u]) {
// if (v == p) continue;
// int64 nt = min({top, pref[idx-1], suff[idx + 1]}) + c;
// dfsr(v, nt, u);
// }
// }
int get (int u, int p) {
for (int i = lg - 1; i >= 0; i--){
if (p & (1 << i)) u = lca[u][i];
}
return u;
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout << fixed; cout << setprecision(10);
cin >> n >> s >> q >> r;
for (int i = 1; i <= n; i++) dp[i] = 1e15;
for (int i = 0; i < n - 1; i++){
int u,v,c;
cin >> u >> v >> c;
ad[u].push_back({v, c});
ad[v].push_back({u, c});
eg.push_back({u, v});
}
for (int i = 0; i < s; i++){
int x;
cin >> x;
is[x] = 1;
}
dfs(r);
// dfsr(r);
while (q--) {
int idx, nd;
cin >> idx >> nd;
auto [x,y] = eg[idx];
if (depth[x] > depth[y]) swap(x, y);
int diff = depth[nd] - depth[x];
// cout << diff << " " << get(nd, diff) << "\n";
if (diff >= 0 && get(nd, diff) == x) {
cout << "0" << "\n";
}
else {
cout << "escaped\n";
}
}
return 0;
}
