/* Murad Eynizade */
#include <bits/stdc++.h>
#define intt long long
#define fyck ios_base::sync_with_stdio(0);cin.tie(0);
#define F first
#define S second
//#define endl '\n'
using namespace std;
const int maxx = 100001 , lg = 17;
int n , m , q , ex , nxt;
int lvl[maxx] , in[maxx] , dp[maxx];
vector< pair<int,int> >v[maxx] , arr;
void dfs(int s,int p) {
dp[s] = 1;
in[s] = ++nxt;
lvl[s] = lvl[p] + 1;
for (auto to : v[s])
if (to.F != p) dfs(to.F , s) , dp[s] += dp[to.F];
}
int x , y , w;
int main() {
fyck
cin>>n>>m>>q>>ex;
for (int i = 1;i<n;i++) {
cin>>x>>y>>w;
v[x].push_back({y , w});
v[y].push_back({x , w});
arr.push_back({x , y});
}
for (int i = 1;i<=m;i++)cin>>x;
dfs(1 , 0);
int i , r;
while (q--) {
cin>>i>>r;
i--;
x = arr[i].F; y = arr[i].S;
if (lvl[x] < lvl[y])swap(x , y);
int res = 0;
res += (in[r] >= in[x] && in[r] <= in[x] + dp[x] - 1);
res += (in[ex] >= in[x] && in[ex] <= in[x] + dp[x] - 1);
if (res & 1)cout<<0<<endl;
else cout<<"escaped"<<endl;
}
}
