#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<ll> vi;
typedef vector<ll> vl;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
struct edge{
ll v;
ll w;
};
bool operator<(edge a, edge b){return a.w > b.w;}
bool operator==(edge a, edge b){return make_pair(a.v,a.w) == make_pair(b.v,b.w);};
typedef vector<edge> ve;
typedef vector<ve> vve;
#define MAX 1e17
struct Node{
ll l,r;
ll v = MAX;
Node *LC = nullptr, *RC = nullptr;
Node(ll l, ll r) : l(l), r(r) {
if(l != r){
LC = new Node(l,(l+r)/2);
RC = new Node((l+r)/2+1,r);
}
}
Node(){}
ll query(ll i, ll j){
if(i > r || j < l) return MAX;
if(i <= l && j >= r) return v;
return min(LC->query(i,j),RC->query(i,j));
}
void update(ll i, ll x){
if(i > r || i < l) return;
if(l == r){
v = min(x,v);
return;
}
LC->update(i,x);
RC->update(i,x);
v = min(LC->v,RC->v);
}
};
struct Solve{
ll N,Q,E;
vi A,B,S,I,R,D,Pre,Inv,Sz,HC,HR;
ve F;
vl W,DS,Ans,H;
vve G,C;
vvi BL,VQ;
vvl DBL;
Node Seg;
void DFS(ll v, edge prev){
F[v] = prev;
D[v] = D[prev.v] + 1;
H[v] = H[prev.v] + prev.w;
Pre.push_back(v);
for(edge e : G[v]){
if(e == prev) continue;
C[v].push_back(e);
DFS(e.v,{v,e.w});
Sz[v] += Sz[e.v];
}
}
void DFS15(ll v, bool ish = 0){
if(ish) HR[v] = HR[F[v].v];
else HR[v] = v;
Pre.push_back(v);
if(C[v].empty()) return;
HC[v] = max_element(C[v].begin(),C[v].end(),[&](edge a, edge b){return Sz[a.v] < Sz[b.v];})->v;
DFS15(HC[v],1);
for(edge e : C[v]){
if(e.v == HC[v]) continue;
DFS15(e.v);
}
}
ll LCA(ll v, ll u){
if(D[u] > D[v]) swap(u,v);
if(D[u] < D[v]){
for(ll d = D[v] - D[u],b = 0;b < BL.size();b++){
if(d & (1<<b)) v = BL[b][v];
}
}
if(u == v) return u;
for(ll b = BL.size()-1;b >= 0;b--) if(BL[b][v] != BL[b][u]) v = BL[b][v],u = BL[b][u];
return BL[0][u];
}
// ll distu(ll u, ll n){
// ll ans = 0;
// for(ll b = 0;b < BL.size();b++){
// if(n & (1<<b)) ans += DBL[b][u], u = BL[b][u];
// }
// }
ll query(ll v, ll r){
ll ans = MAX;
ll c = r;
for(;D[HR[c]] > D[v];c = F[HR[c]].v) ans = min(ans,Seg.query(Inv[HR[c]],Inv[c]));
ans = min(ans,Seg.query(Inv[v],Inv[c]));
return ans;
}
void DFS2(ll v){
for(edge e : C[v]){
DFS2(e.v);
DS[v] = min(DS[v],DS[e.v] + 2*e.w);
}
if(S[v]) DS[v] = -H[v];
Seg.update(Inv[v],DS[v]);
for(ll q : VQ[v]){
if(LCA(v,R[q]) != v) Ans[q] = -1;
else Ans[q] = query(v,R[q]) + H[R[q]];
}
}
Solve(ll N, ll Q, ll E, vi A, vi B, vi S, vi I, vi R, vl W) : N(N), Q(Q), E(E), A(A), B(B), S(S), I(I), R(R), W(W) {
BL.assign(ll(log2(N)+1),vi(N));
DBL.assign(ll(log2(N)+1),vl(N));
D.assign(N,-1);
H.assign(N,0);
Sz.assign(N,1);
G.assign(N,{});
F.assign(N,{0,0});
C.assign(N,{});
HR.assign(N,0);
HC.assign(N,0);
for(ll i = 0;i < N-1;i++){
G[A[i]].push_back({B[i],W[i]});
G[B[i]].push_back({A[i],W[i]});
}
DFS(E,{E,0});
Inv.assign(N,0);
for(ll i = 0;i < N;i++) Inv[Pre[i]] = i;
DFS15(E);
for(ll i = 0;i < N;i++) BL[0][i] = F[i].v, DBL[0][i] = F[i].w;
for(ll p = 1;p < BL.size();p++){
for(ll i = 0;i < N;i++){
BL[p][i] = BL[p-1][BL[p-1][i]];
DBL[p][i] = DBL[p-1][i] + DBL[p-1][BL[p-1][i]];
}
}
for(ll i = 0;i < N-1;i++) if(D[A[i]] < D[B[i]]) swap(A[i],B[i]);
VQ.assign(N,{});
for(ll i = 0;i < Q;i++) VQ[A[I[i]]].push_back(i);
Ans.assign(Q,0);
DS.assign(N,MAX);
Seg = Node(0,N-1);
DFS2(E);
}
};
int main(){
ll N,S,Q,E;
cin >> N >> S >> Q >> E;
E--;
vi A(N-1),B=A,Sh(S),IS(N,0),I(Q),R(Q);
vl W(N-1);
for(ll i = 0;i < N-1;i++){
cin >> A[i] >> B[i] >> W[i];
A[i]--,B[i]--;
}
for(ll i = 0;i < S;i++){
cin >> Sh[i];
IS[--Sh[i]] = 1;
}
for(ll i = 0;i < Q;i++){
cin >> I[i] >> R[i];
I[i]--,R[i]--;
}
Solve sol(N,Q,E,A,B,IS,I,R,W);
for(ll a : sol.Ans){
if(a == -1) cout << "escaped\n";
else if(a == MAX) cout << "oo\n";
else cout << a << '\n';
}
return 0;
}
