#include <bits/stdc++.h>
using namespace std;
#define rep(i,s,e) for (ll i = s; i <= e; ++i)
#define rrep(i,s,e) for (ll i = s; i >= e; --i)
#define pb push_back
#define pf push_front
#define fi first
#define se second
#define all(a) a.begin(), a.end()
typedef long long ll;
typedef pair<ll, ll> ii;
typedef vector<ii> vii;
typedef vector<ll> vi;
typedef vector<double> vd;
typedef vector<string> vs;
typedef vector<ll> vll;
const ll mx = 1e5;
const ll inf = 5e18;
ll d[mx+1], ans[mx+1], sp[mx+1];
vi a;
vii qs[mx+1], adj[mx+1];
ii roads[mx+1];
ll b[mx+1], seg[4*mx+1];
void upd (ll x, ll val, ll l, ll r, ll id) {
if (l==r) {
seg[id] = val;
return;
}
ll mid = (l+r)/2;
if (x<=mid) upd (x, val, l, mid, 2*id);
else upd (x, val, mid+1, r, 2*id+1);
seg[id] = min(seg[2*id], seg[2*id+1]);
}
ll query (ll l, ll r, ll bl, ll br, ll id) {
if (l==bl && r==br) return seg[id];
ll mid = (bl+br)/2;
if (r<=mid) return query(l, r, bl, mid, 2*id);
else if (l>mid) return query (l, r, mid+1, br, 2*id+1);
return min(query (l, mid, bl, mid, 2*id), query(mid+1, r, mid+1, br, 2*id+1));
}
void dfs (ll u, ll p) {
if (!sp[u]) b[u] = inf;
for (ii vw : adj[u]) {
ll v = vw.fi, w = vw.se;
if (v==p) continue;
d[v] = d[u]+1;
dfs (v, u);
if (b[v]<inf) b[u] = min(b[u], b[v]+w);
}
}
void dfs2 (ll u, ll p, ll D) {
a.pb(u);
if (b[u]==inf) upd (a.size()-1, inf, 1, mx, 1);
else upd (a.size()-1, b[u]-D, 1, mx, 1);
for (ii q : qs[u]) {
ll i = q.fi, id = q.se;
if (a[d[roads[i].fi]]==roads[i].fi && a[d[roads[i].se]]==roads[i].se) {
ll res = query (max(d[roads[i].fi], d[roads[i].se]), d[u], 1, mx, 1);
if (res==inf) ans[id] = -2;
else ans[id] = res+D;
}
else ans[id] = -1;
}
for (ii vw : adj[u]) {
ll v = vw.fi, w = vw.se;
if (v==p) continue;
dfs2 (v, u, D+w);
}
a.pop_back();
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
ll n, s, q, e; cin >> n >> s >> q >> e;
rep (i,1,n-1) {
ll u, v, w; cin >> u >> v >> w;
adj[u].pb({v, w});
adj[v].pb({u, w});
roads[i] = {u,v};
}
rep (i,1,s) {
ll x; cin >> x;
sp[x] = 1;
}
rep (i,1,q) {
ll I, R; cin >> I >> R;
qs[R].pb({I,i});
}
a.pb(0);
d[e] = 1;
dfs (e,-1);
dfs2 (e,-1,0);
rep (i,1,q) {
if (ans[i]==-1) cout << "escaped\n";
else if (ans[i]==-2) cout << "oo\n";
else cout << ans[i] << "\n";
}
return 0;
}
