#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
//using namespace __gnu_pbds;
#define F first
#define S second
#define forn(i, n) for(int i = 0; i < n; ++i)
#define forbn(i, b, n) for(int i = b; i < n; ++i)
#define sz(v) (int)v.size()
#define pb push_back
#define eb emplace_back
#define all(v) v.begin(), v.end()
#define mp make_pair
#define at(m, k) (m.find(k) != m.end() ? m[k] : 0)
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef long long ll;
//typedef tree<ii, null_type, less<ii>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
template <class T> inline void mineq(T &a, T b) { a = min(a, b); }
template <class T> inline void maxeq(T &a, T b) { a = max(a, b); }
const int MX = 100 * 1000 + 10;
ll INF = 1ll * 1000 * 1000 * 1000 * 1000 * 1000 * 1000;
struct Seg {
int n;
vector<ll> t;
Seg(int n): n(n) {
t.assign(2 * n, 0);
}
void update(int p, ll val) {
for(t[p += n] = val; p > 1; p >>= 1)
t[p >> 1] = min(t[p], t[p ^ 1]);
}
ll query(int l, int r) {
ll res = INF;
for(l += n, r += n + 1; l < r; l >>=1, r >>= 1) {
if(l & 1) mineq(res, t[l++]);
if(r & 1) mineq(res, t[--r]);
}
return res;
}
};
int n, s, q, e;
vii gr[MX];
ii edge[MX];
int tin[MX], tout[MX];
bool magaz[MX];
int node2depth[MX];
int timer = -1;
Seg mag2rast(MX);
Seg rd(MX);
vii v2q[MX];
ll ans[MX];
void dfs(int node = e, int par = 0, int depth = 0, ll dist = 0) {
tin[node] = ++timer;
mag2rast.update(timer, magaz[node] ? dist : INF);
node2depth[node] = depth;
for(ii nb_w: gr[node]) {
int nb = nb_w.F, w = nb_w.S;
if(nb == par) continue;
dfs(nb, node, depth + 1, dist + w);
}
tout[node] = timer;
}
void dfs2(int node = e, int par = 0, int depth = 0, ll dist = 0) {
ll rast_mag = mag2rast.query(tin[node], tout[node]);
rd.update(depth, rast_mag == INF ? INF : (rast_mag - 2 * dist));
if(sz(v2q[node])) {
for(ii par1qi: v2q[node]) {
int par = par1qi.F, qi = par1qi.S;
int par_depth = node2depth[par];
// cerr << node << ' ' << par_depth << ' ' << depth << '\n';
// cerr << dist << ' ' << rd.query(par_depth, depth) << '\n';
ll tmp = rd.query(par_depth, depth);
ans[qi] = tmp == INF ? INF : dist + tmp;
}
}
for(ii nb_w: gr[node]) {
int nb = nb_w.F, w = nb_w.S;
if(nb == par) continue;
dfs2(nb, node, depth + 1, dist + w);
}
}
bool par_son(int par, int son) {
return tin[par] <= tin[son] && tout[son] <= tout[par];
}
void solve() {
cin >> n >> s >> q >> e;
forbn(i, 1, n) {
int a, b, w;
cin >> a >> b >> w;
edge[i] = mp(a, b);
gr[a].eb(b, w);
gr[b].eb(a, w);
}
forn(_, s) {
int a;
cin >> a;
magaz[a] = true;
}
dfs();
forn(qi, q) {
int i, r;
cin >> i >> r;
int a = edge[i].F, b = edge[i].S;
if(!par_son(a, b))
swap(a, b);
if(par_son(b, r)) {
// cerr << b << ' ' << r << '\n';
v2q[r].eb(b, qi);
} else {
ans[qi] = -1;
}
}
dfs2();
forn(qi, q) {
if(ans[qi] == -1) {
cout << "escaped\n";
}
else if(ans[qi] == INF) {
cout << "oo\n";
}
else {
cout << ans[qi] << '\n';
}
}
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
// freopen("262144.in", "r", stdin);
// freopen("262144.out", "w", stdout);
int t = 1;
// cin >> t;
while(t--) {
solve();
}
}
