/* 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;
int par[maxx][lg] , lvl[maxx];
vector< pair<int,int> >v[maxx] , arr;
void dfs(int s,int p) {
par[s][0] = p;
lvl[s] = lvl[p] + 1;
for (int i = 1;i<lg;i++)
par[s][i] = par[par[s][i - 1]][i - 1];
for (auto to : v[s])
if (to.F != p) dfs(to.F , s);
}
int lca(int x,int y) {
if (lvl[x] < lvl[y])swap(x , y);
int diff = lvl[x] - lvl[y];
for (int i = 0;i<lg;i++)
if ((1 << i) & diff)x = par[x][i];
if (x == y)return x;
for (int i = lg - 1;i>=0;i--) {
if (par[x][i] != par[y][i]) {
x = par[x][i];
y = par[y][i];
}
}
return par[x][0];
}
bool check(int root,int child) {
int diff = lvl[child] - lvl[root];
if (diff < 0)return false;
for (int i = 0;i<lg;i++)
if (diff & (1 << i))child = par[child][i];
return (root == child);
}
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;
int lc = lca(r , x);
if (check(lc , x) && check(lc , y) && r != ex) {
if (check(x , ex) && check(y , ex))cout<<0<<endl;
else if (check(x , r) && check(y , r))cout<<0<<endl;
else cout<<"escaped"<<endl;
}
else cout<<"escaped"<<endl;
}
}
