#include <bits/stdc++.h>
using namespace std;
#define FOR(i, a, b) for(int i=a; i<=b; ++i)
#define pi pair<int, int>
#define f first
#define s second
#define sz(A) (int)(A.size())
#define ll long long
#define pb push_back
#define eb emplace_back
#define V vector
const int base=(1<<17);
const ll inf=1e16;
int n, s, q, e;
struct Edge { int v, u, c, idx; };
struct SegmentTree {
ll T[2*base];
void update(int a, int b, ll x) {
if(a>b) return;
FOR(i, a, b) T[i]+=x;
}
ll query(int a, int b) {
if(a>b) return inf;
ll res=inf;
FOR(i, a, b) res=min(res, T[i]);
return res;
}
} AT;
V<V<Edge>> con;
V<int> pre, post, sajs;
V<V<pi>> todo;
V<ll> odl, odp;
V<Edge> edges;
V<bool> jest_sklepem;
int tpre=0, tpost=0;
void dfs1(int v, int p=0, ll d=0) {
pre[v]=++tpre;
sajs[v]=1;
if(jest_sklepem[v]) AT.update(pre[v], pre[v], d);
for(Edge kr : con[v]) {
int u = kr.u;
int c = kr.c;
if(p==u) continue;
dfs1(u, v, d+c);
sajs[v]+=sajs[u];
}
post[v]=++tpost;
}
bool jest_ojcem(int a, int b) {
return (pre[a]<=pre[b] && post[a]>=post[b]);
}
void dfs2(int v, int p=0) {
for(auto &[idxkr, qidx] : todo[v]) {
int a = edges[idxkr].v;
int b = edges[idxkr].u;
if(!jest_ojcem(a, b)) swap(a, b);
int start = pre[b];
int kon = pre[b]+sajs[b]-1;
if(start<=pre[v] && pre[v]<=kon) {
// zawiera sie w poddrzewie
odp[qidx] = AT.query(start, kon);
} else {
odp[qidx] = min(AT.query(1, start-1), AT.query(kon+1, n));
}
}
for(Edge kr : con[v]) {
int u = kr.u;
int c = kr.c;
int idx = kr.idx;
if(p==u) continue;
// aktualizuj
int start = pre[u];
int kon = pre[u]+sajs[u]-1;
AT.update(start, kon, -c);
AT.update(1, start-1, c);
AT.update(kon+1, n, c);
dfs2(u, v);
// cofnij aktualizacje
AT.update(start, kon, c);
AT.update(1, start-1, -c);
AT.update(kon+1, n, -c);
}
}
int main() {
cin.tie(0) -> ios_base::sync_with_stdio(0);
cin >> n >> s >> q >> e;
con.resize(n+1);
todo.resize(n+1);
pre.resize(n+1);
post.resize(n+1);
odl.resize(n+1);
edges.resize(n);
odp.resize(q+1);
jest_sklepem.resize(n+1);
sajs.resize(n+1);
int a, b, c;
FOR(i, 1, n-1) {
cin >> a >> b >> c;
con[a].pb({a, b, c, i});
con[b].pb({b, a, c, i});
edges[i] = {a, b, c, i};
}
V<int> sklepy;
AT.update(1, n, inf);
FOR(i, 1, s) {
cin>>a;
if(jest_sklepem[a]) continue;
jest_sklepem[a]=1;
sklepy.eb(a);
}
// licz pre, post, AT.T(odl), sajs
dfs1(e);
for(int a : sklepy) {
AT.update(pre[a], pre[a], -inf);
}
int id, v;
FOR(i, 1, q) {
cin >> id >> v;
Edge kr = edges[id];
int a = kr.v;
int b = kr.u;
// a wyzej
if(!jest_ojcem(a, b)) swap(a, b);
if(!(jest_ojcem(e, a) && jest_ojcem(b, v))) odp[i]=-1;
else todo[v].pb({id, i});
}
dfs2(e);
FOR(i, 1, q) {
ll val = odp[i];
if(val==-1) cout << "escaped\n";
else if(val>=1e14) cout << "oo\n";
else cout << val << '\n';
}
}
