#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
#define int long long
#define ii pair<int,int>
#define BIT(mask,x) (((mask)>>(x))&(1))
#define MASK(x) ((LL)(1)<<(x))
#define FOR(i,a,b) for(int i = (a),_b=(b); i<=_b;++i)
#define FORD(i,a,b) for(int i =(a),_b=(b);i>=_b;--i)
template<class X,class Y>
bool maximize(X &x,Y y){
if (x<y) return x=y,true; else return false;
}
template<class X,class Y>
bool minimize(X &x,Y y){
if (x>y) return x=y,true; else return false;
}
template<class T>
void compress(vector<T>&data){
sort(data.begin() , data.end());
data.resize(unique(data.begin() , data.end()) - data.begin());
}
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
LL Rand(LL l,LL r){
return uniform_int_distribution<LL>(l,r)(rng);
}
const int N = (int)1e5;
const LL inf = (LL)1e18;
const int MAXLOG = (int)16;
int par[N+2][MAXLOG+2] = {} , h[N+2] = {};
int sta[N+2] = {} , fin[N+2] = {} , time_dfs = 0;
int u[N+2] , v[N+2] , w[N+2] ;
LL dist[N+2] = {} , f[N+2] = {} , cost[N+2] = {} , up[N+2][MAXLOG+2] = {};
vector<pair<int,int>>ke[N+2] ;
int n , s , q , es;
void add_canh(int u,int v,int w){
ke[u].push_back({v,w}) ,
ke[v].push_back({u,w});
return;
}
void dfs(int u,int p){
sta[u] = ++time_dfs;
h[u] = h[p] + 1;
for(auto&v:ke[u]){
if (v.first==p) continue;
dist[v.first] = dist[u] + v.second;
dfs(v.first , u);
minimize(f[u] , f[v.first] + v.second);
}
cost[u] = f[u] - dist[u];
for(auto&v:ke[u]){
if (v.first==p) continue;
up[v.first][0] = cost[u];
par[v.first][0] = u;
}
fin[u] = time_dfs;
return;
}
bool is_par(int u,int lca){
return sta[lca] <= sta[u] && sta[u] <= fin[lca];
}
LL Get_cost(int u,int lca){
LL res = min(cost[u] , cost[lca]);
for(int i = MAXLOG; i >= 0; --i){
if (h[par[u][i]] >= h[lca]) {
minimize(res , up[u][i]);
u = par[u][i];
}
}
return res;
}
int32_t main(){
ios::sync_with_stdio(false);
cin.tie(0) ; cout.tie(0) ;
#define name "main"
if (fopen(name".inp","r")){
freopen(name".inp","r",stdin);
freopen(name".out","w",stdout);
}
cin>>n>>s>>q>>es;
FOR(i,1,n) f[i] = inf;
FOR(i,1,n-1) {
cin>>u[i]>>v[i]>>w[i];
add_canh(u[i],v[i],w[i]);
}
FOR(i,1,s) {
int v; cin>>v;
f[v] = 0;
}
dfs(es,0);
FOR(j,1,MAXLOG){
FOR(i,1,n) par[i][j] = par[par[i][j-1]][j-1];
FOR(i,1,n) up[i][j] = min(up[i][j-1] , up[par[i][j-1]][j-1]);
}
while(q--){
int id,r; cin>>id>>r;
int x = u[id] , y = v[id];
if (h[x] > h[y]) swap(x,y);
if (is_par(r , y)){
LL ans = dist[r] + Get_cost(r , y);
if (ans >= inf) cout<<"oo"; else cout<<ans;
cout<<'\n';
}
else cout<<"escaped\n";
}
return 0;
}
