#include "bits/stdc++.h"
using namespace std;
#define INF 1000000000
#define INFLL 1000000000000000000ll
#define EPS 1e-9
#define all(x) x.begin(),x.end()
#define pb push_back
#define fi first
#define sc second
using i64 = long long;
using u64 = unsigned long long;
using ld = long double;
using ii = pair<int, int>;
const int N = 1e5 + 100, K = 17, M = 1 << 18;
const i64 L = 1e14L + 10;
vector<ii> adj[N];
int sp[K][N], depth[N], in[N], out[N], t;
int n, s, q, e;
i64 pre[N];
void dfs(int u, int p) {
in[u] = t++;
sp[0][u] = p;
for(int i = 1; (1 << i) <= n; ++i) sp[i][u] = sp[i - 1][sp[i - 1][u]];
for(auto [v, w] : adj[u]) {
if(v == p) continue;
depth[v] = 1 + depth[u];
pre[t] = pre[in[u]] + w;
dfs(v, u);
}
out[u] = t - 1;
}
int LCA(int u, int v) {
if(depth[u] > depth[v]) swap(u, v);
int d = depth[v] - depth[u];
for(int i = 0; (1 << i) <= d; ++i) if(d & (1 << i)) v = sp[i][v];
if(u == v) return u;
for(int i = 31 - __builtin_clz(n); i >= 0; --i) {
if(sp[i][u] == sp[i][v]) continue;
u = sp[i][u], v = sp[i][v];
}
return sp[0][u];
}
i64 dist(int a, int b) {
return pre[in[a]] + pre[in[b]] - 2 * pre[in[LCA(a, b)]];
}
bool is_on_path(int a, int b, int c) {
return dist(a, c) + dist(c, b) == dist(a, b);
}
i64 st[M], lazy[M];
void push(int k) {
if(!lazy[k]) return;
for(int i : {2*k,2*k+1}) {
st[i] += lazy[k];
lazy[i] += lazy[k];
}
lazy[k] = 0;
}
void build(int l, int r, int k = 1) {
lazy[k] = 0;
if(l == r) st[k] = pre[l];
else {
int m = (l + r) / 2;
build(l, m, 2 * k);
build(m + 1, r, 2 * k + 1);
st[k] = min(st[2*k], st[2*k+1]);
}
}
void upd(int l, int r, int x, int lo, int hi, int k = 1) {
if(l > r) return;
else if(hi - lo == r - l) {
st[k] += x;
lazy[k] += x;
} else {
int m = (lo + hi) / 2;
push(k);
upd(l, min(r, m), x, lo, m, 2 * k);
upd(max(m + 1, l), r, x, m + 1, hi, 2 * k + 1);
st[k] = min(st[2*k], st[2*k+1]);
}
}
i64 query(int l, int r, int lo, int hi, int k = 1) {
if(l > r) return INFLL;
else if(hi - lo == r - l) return st[k];
int m = (lo + hi) / 2;
push(k);
return min(query(l, min(r, m), lo, m, 2 * k), query(max(m + 1, l), r, m + 1, hi, 2 * k + 1));
}
vector<ii> queries[N];
ii ed[N];
i64 ans[N];
void dfsquery(int u, int p) {
for(auto [v, w] : adj[u]) {
if(v == p) continue;
upd(in[v], out[v], -w, 0, n - 1);
upd(0, in[v] - 1, w, 0, n - 1);
upd(out[v] + 1, n - 1, w, 0, n - 1);
dfsquery(v, u);
upd(in[v], out[v], w, 0, n - 1);
upd(0, in[v] - 1, -w, 0, n - 1);
upd(out[v] + 1, n - 1, -w, 0, n - 1);
}
for(auto [ed_pos, k] : queries[u]) {
auto [x, y] = ed[ed_pos];
i64 cost;
if(depth[x] < depth[y]) swap(x, y);
if(in[u] < in[x] || in[u] > out[x])
cost = min(query(0, in[x] - 1, 0, n - 1), query(out[x] + 1, n - 1, 0, n - 1));
else
cost = query(in[x], out[x], 0, n - 1);
ans[k] = cost;
}
}
void solve() {
cin >> n >> s >> q >> e;
--e;
for(int i = 1; i < n; ++i) {
int a, b, c;
cin >> a >> b >> c;
--a, --b;
ed[i - 1] = {a, b};
adj[a].pb({b, c});
adj[b].pb({a, c});
}
dfs(0, 0);
vector<bool> shop(n, false);
for(int i = 0; i < s; ++i) {
int v;
cin >> v;
shop[--v] = true;
}
for(int i = 0; i < q; ++i) {
int ed_pos, src;
cin >> ed_pos >> src;
--src, --ed_pos;
auto [u, v] = ed[ed_pos];
if(is_on_path(src, e, u) && is_on_path(src, e, v))
queries[src].pb({ed_pos, i});
else
ans[i] = -1;
}
for(int i = 0; i < n; ++i) if(!shop[i]) pre[in[i]] = INFLL;
build(0, n - 1);
dfsquery(0, 0);
for(int i = 0; i < q; ++i) {
if(ans[i] < 0) cout << "escaped\n";
else if(ans[i] > L) cout << "oo\n";
else cout << ans[i] << '\n';
}
}
int main() {
ios_base :: sync_with_stdio(false);
cin.tie(0);
int t = 1;
//cin >> t;
while(t--) solve();
return 0;
}
