#include <bits/stdc++.h>
using namespace std;
using ll=long long;
const int maxn=(1e5)+1;
vector<int> h(maxn);
vector<vector<int>> jump(maxn,vector<int>(17,-1));
void initialize(){
for(int j=1;j<17;j++){
for(int i=0;i<maxn;i++){
if(jump[i][j-1]!=-1)jump[i][j]=jump[jump[i][j-1]][j-1];
}
}
}
bool isf(int a,int b){
//cout<<a<<" "<<b<<"\n";
for(int i=16;i>0;i--){
if((1<<i)<=(h[a]-h[b])){
a=jump[a][i];
}
}
//cout<<a<<" "<<b<<"\n";
return (b==a)||(b==jump[a][0]);
}
int main(){
ll n,s,k,e,a,b,c;
cin>>n>>s>>k>>e;
vector<pair<int,int>> ed(n);
vector<vector<int>> g(n+1);
vector<int> v(s);
for(int i=1;i<n;i++){
cin>>a>>b>>c;
g[a].push_back(b);
g[b].push_back(a);
ed[i]={min(a,b),max(a,b)};
}
for(int i=0;i<s;i++)cin>>v[i];
queue<int> q;h[e]=0;
q.push(e);
while(!q.empty()){
a=q.front();q.pop();
//cout<<a<<"\n";
for(int u:g[a]){
if(u!=jump[a][0]){
jump[u][0]=a;
h[u]=h[a]+1;
q.push(u);
}
}
}
initialize();
while(k--){
cin>>b>>a;
if(isf(a,ed[b].first)&&isf(a,ed[b].second)){
cout<<"0\n";
}else{
cout<<"escaped\n";
}
}
}
