#ifdef LOCAL
#include "/home/bgopc/template/pch.hpp"
#endif
#include <bits/stdc++.h>
using namespace std;
// * No One Dies a Virgin, Life Fucks Us All
typedef long long ll;
#define nl '\n'
#define ff first
#define ss second
#define pb push_back
#define sik(x) {cout << x << nl; return;}
constexpr ll maxn = 1e5+10, mod = 1e9 + 7, inf = 1e17, SQ = 450, LG = 20;
typedef pair<int, int> pii;
int n, S, s[maxn], in[maxn], out[maxn], T = 1, Ev, seq[maxn], q;
ll seg[maxn << 2], lazy[maxn << 2], ans[maxn], h[maxn];
pii E[maxn];
vector<pii> g[maxn];
vector<pii> Q[maxn];
void build(int l, int r, int id) {
lazy[id] = 0;
if (r - l == 1) {
int v = seq[l];
if (s[v]) seg[id] = h[v];
else seg[id] = inf;
return;
}
int mid = (l + r) >> 1, lc = id << 1, rc = lc | 1;
build(l, mid, lc);
build(mid, r, rc);
seg[id] = min(seg[lc], seg[rc]);
}
inline void tag(int id, ll x) {
seg[id] += x;
lazy[id] += x;
}
inline void relax(int id) {
if (!lazy[id]) return ;
tag(id << 1, lazy[id]);
tag(id << 1 | 1, lazy[id]);
lazy[id] = 0;
}
void update(int ql, int qr, ll x, int l = 1, int r = n+1, int id = 1) {
if (ql <= l && r <= qr) return tag(id, x);
if (qr <= l || r <= ql) return ;
relax(id);
int mid = (l + r) >> 1, lc = id << 1, rc = lc | 1;
update(ql, qr, x, l, mid, lc);
update(ql, qr, x, mid, r, rc);
seg[id] = min(seg[lc], seg[rc]);
}
ll get(int ql, int qr, int l = 1, int r = n+1, int id = 1) {
if (ql <= l && r <= qr) return seg[id];
if (qr <= l || r <= ql) return inf;
relax(id);
int mid = (l + r) >> 1, lc = id << 1, rc = lc | 1;
return min(get(ql, qr, l, mid, lc), get(ql, qr, mid, r, rc));
}
inline bool isfa(int u, int v) {
return in[u] <= in[v] && out[v] <= out[u];
}
void PreDfs(int v, int p = 0) {
in[v] = T ++;
seq[in[v]] = v;
for (auto [u, w] : g[v]) {
if (u != p) {
h[u] = h[v] + w;
PreDfs(u, v);
}
}
out[v] = T;
}
void dfs(int v, int p = 0, ll w = 0) {
update(1, n + 1, w);
update(in[v], out[v], -2 * w);
for (auto [u, j] : Q[v]) {
if (isfa(u, v)) {
ans[j] = min(ans[j], get(in[u], out[u]));
} else {
ans[j] = min(ans[j], get(1, in[u]));
ans[j] = min(ans[j], get(out[u], n + 1));
}
}
for (auto [u, w] : g[v]) {
if (u != p) dfs(u, v, w);
}
update(1, n + 1, -w);
update(in[v], out[v], 2 * w);
}
int32_t main() {
cin.tie(0)->sync_with_stdio(0);
cin >> n >> S >> q >> Ev;
for (int i = 1 , u , v , w ; i < n ; i ++) {
cin >> u >> v >> w;
g[u].pb({v, w});
g[v].pb({u, w});
E[i] = {u, v};
}
for (int i = 1 , c ; i <= S ; i ++) cin >> c, s[c] = 1;
PreDfs(1);
for (int i = 1 ; i < n ; i ++) if (in[E[i].ss] < in[E[i].ff]) swap(E[i].ff, E[i].ss);
build(1, n + 1, 1);
for (int i = 1 , I , u ; i <= q ; i ++) {
cin >> I >> u;
int v = E[I].ss;
if (isfa(v, u) ^ isfa(v, Ev)) {
ans[i] = inf;
Q[u].pb({v, i});
} else ans[i] = -1;
}
dfs(1);
for (int i = 1 ; i <= q ; i ++) {
if (ans[i] == -1) cout << "escaped\n";
else if (ans[i] >= 2e14) cout << "oo\n";
else cout << ans[i] << nl;
}
}
