#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,popcnt,lzcnt")
#define fio ios_base::sync_with_stdio(0);cin.tie(0);
#define ll long long
#define ld long double
#define en exit(0);
#define pb push_back
#define fi first
#define se second
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int N = 1e5 + 5;
const ll INF = 1e18 + 5;
vector<array<int, 3> > g[N];
bool shop[N];
int e;
ll dfs(int u, int p, int ban_id, ll curd = 0)
{
if(u == e)
return -1;
ll dist = (shop[u] ? curd : INF);
for(auto [v, w, id] : g[u])
{
if(id == ban_id || v == p)
continue;
dist = min(dist, dfs(v, u, ban_id, curd + w));
}
return dist;
}
int main()
{
fio
// ifstream cin("in.in");
int n, s, q;
cin >> n >> s >> q >> e;
for(int i = 1;i < n;i++)
{
int u, v, w;
cin >> u >> v >> w;
g[u].pb({v, w, i});
g[v].pb({u, w, i});
}
for(int i = 1;i <= s;i++)
{
int p;
cin >> p;
shop[p] = 1;
}
while(q--)
{
int i, r;
cin >> i >> r;
ll d = dfs(r, r, i);
if(d == -1)
cout << "escaped";
else if(d == INF)
cout << "oo";
else
cout << d;
cout << "\n";
}
return 0;
}
