#include <bits/stdc++.h>
#define int long long
#define pb push_back
#define F first
#define S second
#define all(a) a.begin(),a.end()
#define pii pair<int,int>
using namespace std ;
const int maxn = 5e5 + 100 , mod = 1e9 + 7 , inf = 1e17 , lg= 23 ;
int b[maxn] , dp[maxn][lg+10] , t[maxn] , mark[maxn] , wp[maxn] , ed[maxn] , par[maxn][lg+10] , st[maxn] , en[maxn] ;
int dis[maxn] , dis2[maxn];vector<pii> G[maxn] ;
int cnt =1 , mark2[maxn] ;
void dfs(int v){
mark[v] = 1;
int m1 = 0, m2 = 0 ;
b[v] = inf ;
st[v] = cnt ;cnt++ ;
for(int i =0 ; i < G[v].size() ; i++){
int u = G[v][i].F , w = G[v][i].S ;
if(mark[u] == 1)continue ;
wp[u] = w ;
par[u][0] = v ;
dis[u] = dis[v]+ w ;
dis2[u] = dis2[v] +1 ;
dfs(u) ;
if(m1 == 0 || (b[u] + wp[u]) < (b[m1] + wp[m1])){
swap(m1 , m2) ;
m1= u ;
}else if(m2 == 0 || (b[u] + wp[u]) < (b[m2] + wp[m2])){
m2 = u ;
}
}
if(t[v] == 0){
b[v] = b[m1] + wp[m1] ;
}else {
b[v] = 0 ;
m1 = m2 = v;
}
for(int i =0 ; i < G[v].size() ; i++){
int u = G[v][i].F , w = G[v][i].S ;
if(mark2[u] == 1)continue ;
int f = m1 ;
mark2[u] = 1;
if(m1 == u)f =m2 ;
dp[u][0] = min(wp[f] + wp[u] + b[f] , inf ) ;
}
en[v] = cnt ;cnt++ ;
}
vector <pii> vec ;
signed main(){
ios_base::sync_with_stdio(false);cin.tie(0);
int n , s , q , e ;
cin >> n >> s>> q >> e ;
for(int i =1; i <= n-1 ; i++){
int v , u , w ;
cin >> v >> u >> w ;
G[v].pb({u,w}) ;
G[u].pb({v,w}) ;vec.pb({v , u}) ;
}
for(int i =1 ; i <= s ; i++){
int f ;cin >> f;
t[f] = 1;
}
b[0] = inf ;
dfs(e) ;
for(int j = 1 ; j <= lg; j++){
for(int i =1 ; i <= n ; i++){
par[i][j] = par[par[i][j-1]][j-1] ;
int x = par[i][j-1] ;
dp[i][j] = (((dis[i] - dis[x] + dp[x][j-1]) < dp[i][j-1]) ? (dis[i] - dis[x] + dp[x][j-1]) : dp[i][j-1] );
}
}
while(q--){
int id , k ;
cin >> id >> k ;
int v = vec[id-1].F , u =vec[id-1].S ;
if(dis[v] < dis[u])swap(v , u) ;
if(!(st[k] >= st[v] && en[k] <= en[v])){
cout << "escaped\n" ;
continue ;
}
int ans = b[k] ;
int x = dis2[k] - dis2[v] ;
int k1 = k ;
for(int i = lg ; i >=0 ; i--){
if(x>>i&1){
if(ans > (dis[k1] - dis[k] + dp[k][i])){
ans = (dis[k1] - dis[k] + dp[k][i]) ;
}
k = par[k][i] ;
}
}
if(ans >= inf){
cout << "oo\n";
continue ;
}
cout << ans << "\n" ;
}
}
