#pragma GCC target("avx2")
#pragma GCC optimization("O3")
#pragma GCC optimization("unroll-loops")
#include<bits/stdc++.h>
//#include "boxes.h"
#define rc(x) return cout<<x<<endl,0
#define pb push_back
#define mkp make_pair
#define in insert
#define er erase
#define fd find
#define fr first
#define sc second
typedef long long ll;
typedef long double ld;
const ll INF=0x3f3f3f3f3f3f3f3f;
const ll llinf=(1LL<<61);
const int inf=(1<<30);
const int nmax=1e5+50;
const int mod=1e9+7;
using namespace std;
int n,s,q,e,x,y,w,ex[nmax],ey[nmax],ew[nmax],par[nmax][20],fin[nmax],fout[nmax],h[nmax],b[nmax],i,tin;
vector<pair<int,int> >a[nmax];
void build(int x,int p,int z)
{
par[x][0]=p;
h[x]=h[p]+z;
fin[x]=++tin;
for(int i=1;i<18;i++)
{
par[x][i]=par[par[x][i-1]][i-1];
}
for(int i=0;i<a[x].size();i++)
{
int y=a[x][i].fr;
if(y==p)continue;
build(y,x,a[x][i].sc);
}
fout[x]=++tin;
}
int anc(int x,int y)
{
return fin[x]<=fin[y] && fout[y]<=fout[x];
}
int main()
{
//freopen("sol.in","r",stdin);
//freopen("sol.out","w",stdout);
//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
ios_base::sync_with_stdio(false);cin.tie(0);cerr.tie(0);cout.tie(0);
cin>>n>>s>>q>>e;
for(i=1;i<n;i++)
{
cin>>x>>y>>w;
a[x].pb(mkp(y,w));
a[y].pb(mkp(x,w));
ex[i]=x,ey[i]=y,ew[i]=w;
}
for(i=1;i<=s;i++)
{
cin>>x;
b[x]=1;
}
build(1,1,0);
while(q--)
{
cin>>x>>y;
if(h[ex[x]]>h[ey[x]])swap(ex[x],ey[x]);
x=ey[x];
if((anc(x,y) && anc(x,e)) || (!anc(x,y) && !anc(x,e)))cout<<"escaped\n";
else
{
cout<<0<<endl;
}
}
return 0;
}
