#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pint = pair<int, int>;
const ll INF = 1e18;
struct St {
int off;
vector<ll> st;
St(int l, int r) : off(-l + r - l + 1), st((r - l + 1) << 1, INF) {}
ll query(int l, int r) {
ll ret = INF;
for (l += off, r += off; l < r; l >>= 1, r >>= 1) {
if (l & 1) ret = min(ret, st[l++]);
if (r & 1) ret = min(ret, st[--r]);
}
return ret;
}
void update(int i, ll v) {
for (st[i += off] = v; i >>= 1;) st[i] = min(st[i << 1], st[i << 1 | 1]);
}
} *st[100001];
int N, S, Q, E, a[100000], b[100000], w[100000], par[100001], depth[100001], sz[100001], s[100001], e[100001], heavy[100001], head[100001];
ll shop[100001], ps[100001];
vector<pint> adj[100001];
void dfs(int i) {
for (auto [j, d]: adj[i]) {
if (j == par[i]) continue;
depth[j] = depth[i] + 1;
ps[j] = ps[i] + d;
s[j] = e[j] = e[i];
par[j] = i;
dfs(j);
shop[i] = min(shop[i], shop[j] + d);
sz[i] += sz[j];
e[i] = e[j] + 1;
if (sz[j] >= sz[heavy[i]]) heavy[i] = j;
}
sz[i]++;
}
void hld(int i) {
if (heavy[i]) {
head[heavy[i]] = head[i];
hld(heavy[i]);
st[i] = st[heavy[i]];
} else st[i] = new St{depth[head[i]], depth[i]};
for (auto [j, d]: adj[i]) {
if (j == par[i] or j == heavy[i]) continue;
head[j] = j;
hld(j);
}
}
ll query(int i, int j) {
if (not i) return INF;
if (depth[head[i]] >= depth[j]) return min(st[i]->query(depth[head[i]], depth[i] + 1), query(par[head[i]], j));
return st[i]->query(depth[j], depth[i] + 1);
}
int main() {
cin >> N >> S >> Q >> E;
for (int i = 1; i <= N - 1; ++i) {
cin >> a[i] >> b[i] >> w[i];
adj[a[i]].emplace_back(b[i], w[i]);
adj[b[i]].emplace_back(a[i], w[i]);
}
memset(shop, 0x3f, sizeof shop);
while (S--) {
int i;
cin >> i;
shop[i] = 0;
}
dfs(E), hld(E);
for (int i = 1; i <= N; ++i) {
st[i]->update(depth[i], shop[i] - ps[i]);
}
while (Q--) {
int i, r;
cin >> i >> r;
if (depth[a[i]] > depth[b[i]]) swap(a[i], b[i]);
if (s[r] < s[b[i]] or e[r] > e[b[i]]) cout << "escaped\n";
else {
ll ans = query(r, b[i]) + ps[r];
if (ans >= INF) cout << "oo\n";
else cout << ans << endl;
}
}
}
