#include <bits/stdc++.h>
#define ll long long
#define int long long
#define pb push_back
#define fi first
#define se second
#define lf (id<<1)
#define rg ((id<<1)|1)
#define md ((l+r)>>1)
#define ld long double
using namespace std;
const int MAXN = 2e5+10;
const int INF = 1e18+10;
const int LOG = 18;
typedef pair<int,int> pii;
typedef pair<pii,int> ipii;
struct seg {
int st[4*MAXN];
void bd(int id, int l, int r){
st[id] = INF;
if(l==r) return;
bd(lf, l, md); bd(rg, md+1, r);
}
int que(int id, int l, int r, int x, int y){
if(x<=l && r<=y) return st[id];
if(r<x || y<l) return INF;
return min(que(lf, l, md, x, y), que(rg, md+1, r, x, y));
}
int upd(int id, int l, int r, int x, int p){
if(l==r && x==l) return st[id] = p;
if(x<l || r<x) return st[id];
return st[id] = min(upd(lf, l, md, x, p), upd(rg, md+1, r, x, p));
}
} A;
int n, s, q, e;
int u[MAXN], v[MAXN], w[MAXN], ty[MAXN];
vector <pii> adj[MAXN], que[MAXN];
int dis[MAXN], dep[MAXN], dw[MAXN], ans[MAXN], up[MAXN];
void pre(int nw, int par){
// cout << nw << ' ' << par << " nw\n";
dep[nw] = dep[par]+1;
dis[nw] = INF;
for(auto ed : adj[nw]){
int nx = ed.fi, wei = ed.se;
if(nx == par) continue;
up[nx] = up[nw]+wei;
pre(nx, nw);
dis[nw] = min(dis[nw], dis[nx]+wei);
}
if(ty[nw]) dis[nw] = 0;
}
vector <int> vec;
void dfs(int nw, int par){
A.upd(1, 1, n, nw, dis[nw]-up[nw]);
vec.pb(nw);
for(auto ed : adj[nw]){
int nx = ed.fi, wei = ed.se;
if(nx == par) continue;
dfs(nx, nw);
}
for(auto in : que[nw]){
int ed = in.fi, idx = in.se;
// cout << idx << ' ' << dw[ed] << ' '<< dep[dw[ed]] << " idx\n";
// for(auto in : vec) cout << in << ' ';
// cout << '\n';
if(vec.size()-1 < dep[dw[ed]] || vec[dep[dw[ed]]] != dw[ed]){
ans[idx] = -1; continue;
}
ans[idx] = 0;
// ans[idx] = A.que(1, 1, n, dw[idx], dep[nw])+up[nw];
}
vec.pop_back();
A.upd(1, 1, n, nw, INF);
}
signed main(){
cin >> n >> s >> q >> e;
for(int i=1; i<=n-1; i++){
cin >> u[i] >> v[i] >> w[i];
adj[u[i]].pb({v[i], w[i]});
adj[v[i]].pb({u[i], w[i]});
}
A.bd(1, 1, n);
for(int i=1; i<=s; i++){
int c; cin >> c; ty[c] = 1;
}
pre(e, 0);
for(int i=1; i<=n-1; i++){
dw[i] = (dep[u[i]] < dep[v[i]] ? v[i] : u[i]);
}
// for(int i=1; i<=n; i++){
// cout << i << ' ' << dw[i] << ' ' << dis[i] << " dw\n";
// }
for(int i=1; i<=q; i++){
int ed, idx; cin >> ed >> idx;
que[idx].pb({ed, i});
}
vec.pb(-1);
dfs(e, 0);
for(int i=1; i<=q; i++){
if(ans[i] == -1) cout << "escaped\n";
else if(ans[i] >= INF) cout << "oo\n";
else cout << ans[i] << '\n';
}
}
