#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
//using namespace __gnu_pbds;
#define int long long
#define mod 1000000007
#define base 7001
#define base2 757
// #define pi acos(-1)
#define double long double
//#define ordered_set tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update>
//#define ordered_multiset tree<int, null_type, less_equal<int>, rb_tree_tag,tree_order_statistics_node_update>
#pragma GCC optimize("O3,Ofast,unroll-loops")
#pragma GCC target("avx2,sse3,sse4,avx")
constexpr int maxn = 1000001;
const int N = 1 << (int)(ceil(log2(maxn)));
int n, s, q, e, dis[1001];
array<int,2> edge[1001];
bool vis[1001], shop[1001];
vector<pair<int,int>>adj[1001];
int dfs(int i, int a, int b)
{
vis[i] = 1;
int mn = INT_MAX;
for (auto [j, w] : adj[i])
{
if ((j == a && i == b) || (j == b && i == a))
continue;
if (!vis[j])
{
dis[j] = dis[i] + w;
mn = min(dfs(j, a, b), mn);
}
}
if (shop[i])
return min(dis[i], mn);
return mn;
}
signed main()
{
cin.tie(0) -> sync_with_stdio(0);
cin >> n >> s >> q >> e;
for (int i = 1; i < n; i++)
{
int u, v, w;
cin >> u >> v >> w;
edge[i] = {u, v};
adj[u].push_back({v, w});
adj[v].push_back({u, w});
}
for (int i = 0; i < s; i++)
{
int u;
cin >> u;
shop[u] = 1;
}
while (q--)
{
memset(vis, 0, sizeof vis);
memset(dis, 0, sizeof dis);
int i, r;
cin >> i >> r;
int mn = dfs(r, edge[i][0], edge[i][1]);
if (vis[e]) cout << "escaped\n";
else if (mn != INT_MAX) cout << mn << "\n";
else cout << "oo\n";
}
}
