#include <bits/stdc++.h>
using namespace std ;
#define i64 int64_t // typecast using i64(x)
#define int int64_t
#define ld long double
#define f(i,a,b) for(int i=a; i<b; ++i)
#define endl '\n'
#define PQ priority_queue
#define LB lower_bound
#define UB upper_bound
#define fr first
#define sc second
#define all(a) (a).begin(),(a).end()
#define allr(a) (a).rbegin(),(a).rend()
#define sz(x) ((int)(x).size())
//#ifndef ONLINE_JUDGE
template<typename T>
void __p(T a) {
cout<<a;
}
template<typename T, typename F>
void __p(pair<T, F> a) {
cout<<"{";
__p(a.first);
cout<<",";
__p(a.second);
cout<<"}\n";
}
template<typename T>
void __p(std::vector<T> a) {
cout<<"{";
for(auto it=a.begin(); it<a.end(); it++)
__p(*it),cout<<",}\n"[it+1==a.end()];
}
template<typename T, typename ...Arg>
void __p(T a1, Arg ...a) {
__p(a1);
__p(a...);
}
template<typename Arg1>
void __f(const char *name, Arg1 &&arg1) {
cout<<name<<" : ";
__p(arg1);
cout<<endl;
}
template<typename Arg1, typename ... Args>
void __f(const char *names, Arg1 &&arg1, Args &&... args) {
int bracket=0,i=0;
for(;; i++)
if(names[i]==','&&bracket==0)
break;
else if(names[i]=='(')
bracket++;
else if(names[i]==')')
bracket--;
const char *comma=names+i;
cout.write(names,comma-names)<<" : ";
__p(arg1);
cout<<" | ";
__f(comma+1,args...);
}
//#endif
void setIO(string s = "") {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin.exceptions(cin.failbit);
if(sz(s)){
freopen((s+".in").c_str(),"r",stdin);
freopen((s+".out").c_str(),"w",stdout);
}
}
const int INF = 1e16 ;
/**
* Description: Euler Tour, LCA, kth_ancestor
* source: own
* The root points to itself.
* 0 based indexing
* Time: O(N\log N) build, O(log N) LCA
* Source: cp-algorithm, own
* Verification: to be done
* for kth_ancestor : https://cses.fi/problemset/result/1573131/
* for lca : https://cses.fi/problemset/result/1573158/
*/
struct LCA {
int N, timer = 0, LOG ;
vector< vector<int> > up, dis, val ;
vector< vector< array<int,2> > > adj ;
vector<int> tin, tout, depth, C, vec ;
void init(int _N) {
N = _N ; LOG = log2(N) + 5 ;
adj.resize(N) ;
up.resize(N, vector<int> (LOG)) ;
dis.resize(N, vector<int> (LOG)) ;
val.resize(N, vector<int> (LOG, INF)) ;
tin = tout = depth = vector<int> (N) ;
vec = vector<int> (N,INF) ;
}
void ae(int x, int y,int w) { // add edge
adj[x].push_back({y,w}), adj[y].push_back({x,w});
}
void dfs(int v, int p,int w){
tin[v] = ++timer;
up[v][0] = p ; dis[v][0] = w ;
for(int i = 1; i < LOG; i++){
up[v][i] = up[up[v][i-1]][i-1] ;
dis[v][i] = dis[v][i-1] + dis[up[v][i-1]][i-1] ;
}
for(auto [u,_w]:adj[v]) if(u != p){
depth[u] = depth[v] + 1 ; dfs(u,v,_w) ;
}
tout[v] = ++timer ;
}
void gen(int R = 0) {
depth[R] = 0 ;
dfs(R,R,0);
dfs2(R,R) ;
f(i,0,N){
val[i][0] = min(vec[i],dis[i][0] + vec[up[i][0]]) ;
}
f(j,1,LOG){
f(i,0,N){
val[i][j] = min(val[i][j-1],dis[i][j-1] + val[up[i][j-1]][j-1]) ;
}
}
}
void getC(vector<int> _C){
C = _C ;
for(auto i:C){
vec[i] = 0 ;
}
}
void dfs2(int i,int p){
for(auto [j,w]:adj[i]) if(j!=p) {
dfs2(j,i) ; vec[i] = min(vec[i],w + vec[j]) ;
}
}
bool is_ancestor(int u, int v){
return tin[u] <= tin[v] && tout[u] >= tout[v];
}
int lca(int u, int v){
if( is_ancestor(u,v) ) return u;
if( is_ancestor(v,u) ) return v;
for(int i=LOG-1;i>=0;--i) {
if( !is_ancestor(up[u][i],v) ){
u = up[u][i] ;
}
}
return up[u][0];
}
int dist(int u, int v) {
return depth[u] + depth[v] - 2 * depth[lca(u,v)];
}
int query(int i,int k){
if(k == 0) return vec[i] ;
int cur = dis[i][0] , ans = vec[i] ; i = up[i][0] ; k--;
for(int j = LOG - 1; j >= 0; --j){
if( (int(1) << j) <= k ){
ans = min(ans, cur + val[i][j]) ;
cur += dis[i][j] ;
k -= (int(1) << j) ;
i = up[i][j] ;
}
}
assert(k == 0) ;
ans = min(ans,cur + vec[i]) ;
return ans ;
}
};
signed main(){
setIO() ;
int N, S, Q, E; cin >> N >> S >> Q >> E ; --E;
vector<array<int,2> > edges ;
LCA tree ; tree.init(N) ;
f(i,0,N-1){
int A, B, W; cin >> A >> B >> W ; --A,--B;
edges.push_back({A,B}) ; tree.ae(A,B,W) ;
}
vector<int> C(S) ;
f(i,0,S){ cin >> C[i] ; --C[i] ;}
tree.getC(C) ;
tree.gen(E) ;
while(Q--){
int I, R; cin >> I >> R ; --I,--R;
int temp = tree.lca(edges[I][0],edges[I][1]) ;
temp = (temp == edges[I][0] ? edges[I][1] : edges[I][0]) ;
if( tree.lca(temp,R) != temp ){
cout << "escaped\n" ; continue ;
}
int K = tree.depth[R] - tree.depth[temp] ;
int ans = tree.query(R,K) ;
if(ans >= INF){
cout << "oo\n" ;
}else{
cout << ans << endl ;
}
}
}
