#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define fi first
#define se second
const ll MAXN = 4e5 + 5, INF = 1e18, MOD = 1e9 + 7, MAXV = 4e5 + 2;
ll n, m, i, j, k, p, dem, cnt, ans, S, Q, root, dtr[MAXN], shop[MAXN], mark[MAXN], preshop[MAXN], par[MAXN], dist[MAXN], chain[MAXN], headchain[MAXN], st[MAXN], en[MAXN], cntchain = 1, de[MAXN], sz[MAXN];
vector<pair<ll, ll>> adj[MAXN];
pair<ll, ll> edge[MAXN];
ll dfs(ll st) {
sz[st] = 1;
if (shop[st] & 1) preshop[st] = st;
ll best = INF;
for (auto x : adj[st]) {
if (de[x.fi]) continue;
de[x.fi] = de[st] + 1;
dtr[x.fi] = dtr[st] + x.se;
par[x.fi] = st;
preshop[x.fi] = preshop[st];
best = min(best, dfs(x.fi) + x.se);
sz[st] += sz[x.fi];
}
if (shop[st] & 1) best = 0;
dist[st] = best;
return best;
}
void HLD(ll u) {
if (!headchain[cntchain]) headchain[cntchain] = u;
chain[u] = cntchain;
ll v = -1, maxsz = -1;
for (auto x : adj[u])
if (x.fi != par[u] && sz[x.fi] > maxsz) maxsz = sz[x.fi], v = x.fi;
if (v != -1) HLD(v);
for (auto x : adj[u])
if (x.fi != par[u] && x.fi != v) {
++cntchain;
HLD(x.fi);
}
en[u] = cntchain;
}
ll lca(ll u, ll v) {
while (chain[u] != chain[v]) {
if (de[headchain[chain[u]]] > de[headchain[chain[v]]])
u = par[headchain[chain[u]]];
else
v = par[headchain[chain[v]]];
}
return (de[u] < de[v] ? u : v);
}
ll tinh(ll u, ll v) {
return de[u] + de[v] - 2 * de[lca(u, v)];
}
void check(ll u, ll st) {
ll stchain = chain[u], enchain = en[u], cur = preshop[st];
if (cur > 0 && de[cur] >= de[u]) ans = min(ans, dtr[st] - dtr[cur]);
for (ll i = stchain; i <= enchain; i++) {
ll pa = par[headchain[i]];
if (!pa || de[pa] < de[u]) continue;
ans = min(ans, dist[pa] + dtr[pa] + dtr[st] - 2 * dtr[lca(st, pa)]);
}
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n >> S >> Q >> root;
for (i = 1; i < n; i++) {
ll u, v, c;
cin >> u >> v >> c;
edge[i] = {u, v};
adj[u].pb({v, c});
adj[v].pb({u, c});
}
for (i = 1; i <= S; i++) cin >> k, shop[k] = 1;
de[root] = 1;
fill(dist + 1, dist + n + 1, INF);
dfs(root);
HLD(root);
for (i = 1; i <= Q; i++) {
ll block, E;
cin >> block >> E;
ll u = edge[block].fi, v = edge[block].se;
if (de[u] < de[v]) swap(u, v);
ans = INF;
if (tinh(u, E) + tinh(v, root) + 1 == tinh(E, root)) {
ans = min(ans, dist[E]);
ans = min(ans, dist[u] - dtr[u] + dtr[E]);
check(u, E);
if (ans >= INF)
cout << "oo\n";
else
cout << ans << '\n';
} else
cout << "escaped\n";
}
}
