#include <bits/stdc++.h>
#define pii pair<int, int>
#define fi first
#define se second
#define ll long long
using namespace std;
const int N = 1e5+5;
const ll INF = 1e18+8;
vector<array<ll, 2>> edges[100'002];
vector<array<ll, 2>> eg;
bool shop[100'002];
int tin[N], tout[N];
int tim=0;
ll e;
ll dfs(ll u, ll block, ll p=0, ll dist=0){
tim++;
tin[u]=tim;
ll tta;
if(shop[u])
tta=dist;
else tta=INF;
for(auto x : edges[u]){
if(x[0]!=p){
tta=min(tta, dfs(x[0], block, u, dist+x[1]));
}
}
tout[u]=tim;
return tta;
}
bool isinside(int a, int b){
//vai a ir ieks b
if(tin[b]<=tin[a] && tout[b]>=tout[a])
return 1;
else
return 0;
}
int main()
{
ll n, s, q; cin>>n>>s>>q>>e;
eg.push_back({0, 0});
for(ll i=1; i<n; i++){
ll a, b, w; cin>>a>>b>>w;
edges[a].push_back({b, w});
edges[b].push_back({a, w});
eg.push_back({a, b});
}
for(ll i=0; i<s; i++){
ll s; cin>>s;
shop[s]=1;
}
dfs(e, -1);
// for(int i=0; i<n; i++){
// cout<<tin[i]<<' '<<tout[i]<<endl;
// }
for(ll i=0; i<q; i++){
ll u, block; cin>>block>>u;
// pienem a ir 1 un b ir 1
int a=eg[block][0], b=eg[block][1];
int atb=-1;
// cout<<"SIe: "<<a<<' '<<isinside(u, a)<<' '<<b<<' '<<isinside(u, b)<<endl;
if(isinside(u, a) && isinside(u, b))
atb=0;
if(atb==-1)
cout<<"escaped"<<endl;
else if(atb==INF)
cout<<"oo"<<endl;
else
cout<<atb<<endl;
}
return 0;
}
/*
5 5 3 1
1 2 3
1 3 2
3 4 1
3 5 2
1
2
3
4
5
2 2
2 5
4 5
*/
