// Om Namah Shivaya
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x, y) ((x + y - 1) / (y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
#define rep(i, n) for(int i = 0; i < n; ++i)
#define rep1(i, n) for(int i = 1; i <= n; ++i)
#define rev(i, s, e) for(int i = s; i >= e; --i)
#define trav(i, a) for(auto &i : a)
template<typename T>
void amin(T &a, T b) {
a = min(a, b);
}
template<typename T>
void amax(T &a, T b) {
a = max(a, b);
}
#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif
/*
*/
const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
struct DSU {
vector<int> par, rankk, siz;
vector<array<int, 3>> history;
DSU() {
}
DSU(int n) {
init(n);
}
void init(int n) {
par = vector<int>(n + 1);
rankk = vector<int>(n + 1);
siz = vector<int>(n + 1);
rep(i, n + 1) create(i);
}
void create(int u) {
par[u] = u;
rankk[u] = 0;
siz[u] = 1;
}
int find(int u) {
if (u == par[u]) return u;
else return par[u] = find(par[u]);
}
bool same(int u, int v) {
return find(u) == find(v);
}
void merge(int u, int v) {
u = find(u), v = find(v);
history.pb({u, par[u], rankk[u]});
history.pb({v, par[v], rankk[v]});
if (u == v) return;
if (rankk[u] == rankk[v]) rankk[u]++;
if (rankk[u] < rankk[v]) swap(u, v);
par[v] = u;
siz[u] += siz[v];
}
void rollback(ll times) {
times *= 2;
while (times--) {
if (history.empty()) {
exit(108);
}
auto [u, pa, rnk] = history.back();
history.pop_back();
par[u] = pa;
rankk[u] = rnk;
}
}
};
void solve(int test_case)
{
ll n, s, q, des; cin >> n >> s >> q >> des;
vector<array<ll, 3>> edges(n);
rep1(i, n - 1) {
ll u, v, w; cin >> u >> v >> w;
edges[i] = {u, v, w};
}
vector<ll> spl(n + 5);
rep1(i, s) cin >> spl[i];
while (q--) {
ll id, u; cin >> id >> u;
DSU dsu(n + 5);
rep1(i, n - 1) {
if (i != id) {
auto [u, v, w] = edges[i];
dsu.merge(u, v);
}
}
if (dsu.same(u, des)) {
cout << "escaped" << endl;
}
else {
cout << 0 << endl;
}
}
}
int main()
{
fastio;
int t = 1;
// cin >> t;
rep1(i, t) {
solve(i);
}
return 0;
}
