#include <bits/stdc++.h>
#define int long long
using namespace std;
const long long N = 2e5 + 5;
const long long lg = 20;
int a[N];
int start[N];
int en[N];
int weight[N];
int tim = 0;
int p[N];
int nearest[N];
vector<pair<int, int>> graph[N];
vector<pair<int, int>> edges;
int sp[N][lg];
int st[N][lg];
// const int N = 2e5 + 3;
int dist[N];
int mask;
void go_up(int &k, int binary)
{
for (int i = 0; i < lg; i++)
{
mask = 1LL << i;
if ((binary & mask) != 0)
{
k = sp[k][i];
}
}
}
int same_at_height(int u, int v)
{
if (u == v)
return v;
for (int i = lg - 1; i >= 0; i--)
{
if (sp[u][i] != sp[v][i])
{
u = sp[u][i];
v = sp[v][i];
}
}
return sp[u][0];
}
int lca(int u, int v)
{
if (dist[u] > dist[v])
swap(u, v);
// cout << u << ' ' << v << endl;
// cout << dist[u] << ' ' << dist[v] << endl;
int diff = dist[v] - dist[u];
go_up(v, diff);
// cout << u << ' ' << v << endl;
if (u == v)
return u;
return same_at_height(u, v);
}
// Function to initialize the Sparse Table
void initialize(int n)
{
// int n = ls.size();
for (int i = 0; i <= n; i++)
{
sp[i][0] = p[i];
st[i][0] = nearest[i] - weight[i];
}
for (int i = 1; i < lg; i++)
{
for (int j = 0; j <= n; j++)
{
st[j][i] = min(st[j][i - 1], st[sp[j][i - 1]][i - 1]);
sp[j][i] = sp[sp[j][i - 1]][i - 1];
}
}
}
int get(int l, int r)
{
// l=st[l][0];
int ans = 1e18;
// get rth ancestor of l
for (int i = lg - 1; i >= 0; i--)
{
if ((r >> i) & 1)
{
ans = min(ans, st[l][i]);
l = sp[l][i];
}
}
return ans;
}
void dfs(int node, int parent)
{
// cout << "visited " << node << endl;
p[node] = parent;
start[node] = tim++;
dist[node] = dist[parent] + 1;
for (auto i : graph[node])
{
if (i.first == parent)
continue;
weight[i.first] = i.second + weight[node];
dfs(i.first, node);
// cout << node << " " << i.first << ' ' << nearest[i.first] << ' ' << i.second << endl;
nearest[node] = min(nearest[node], nearest[i.first] + i.second);
}
en[node] = tim;
}
void solve()
{
int n, s, q, E;
int e;
cin >> n >> s >> q >> E;
int u, v, w;
for (int i = 1; i < n; i++)
{
cin >> u >> v >> w;
edges.push_back({u, v});
graph[u].push_back({v, w});
graph[v].push_back({u, w});
}
fill(nearest, nearest + N, 1e15);
for (int i = 0; i < s; i++)
{
// shops
cin >> e;
nearest[e] = 0;
}
dfs(E, 0);
initialize(n + 1);
// int q;
// cin >> q;
// for (int i = 0; i < n; i++)
// {
// cout << st[i + 1][0] << ' ';
// }
// cout << endl;
for (int i = 0; i < q; i++)
{
cin >> u >> v;
u--;
int tutau;
// road u is cut
if (start[edges[u].first] > start[edges[u].second])
swap(edges[u].first, edges[u].second);
tutau = edges[u].second;
// cout << lca(3, 5) << endl;
// cout << sp[5][0] << endl;
if (lca(tutau, v) != tutau)
{
cout << "escaped\n";
continue;
}
// cout << tutau << ' ' << edges[u].second << ' ' << v << endl;
int up = dist[v] - dist[tutau];
// cout << dist[v] << ' ' << dist[tutau] << endl;
// /
// cout << up << endl;
// cout << p[5] << endl;
// cout << st[5][1] << endl;
int ans = get(v, up + 1) + weight[v];
if (ans == 1e15)
{
cout << "oo" << endl;
}
else
{
cout << ans << endl;
}
}
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
int t = 1;
// cin >> t;
for (int i = 1; i <= t; i++)
{
// cout << "Case #" << i << ':' << ' ';
solve();
cout << endl;
}
return 0;
}
