#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int mxN = 1e5 + 100;
const ll INF = 1e18;
bool shop[mxN];
int st[mxN], en[mxN], seg[mxN * 12], edg[mxN], tim = 0;
vector<vector<int>> adj[mxN];
void update(int node, int start, int end, int idx, int val)
{
if (start == end)
{
seg[node] = val;
return;
}
int mid = start + (end - start) / 2;
if (idx <= mid)
update(node * 2 + 1, start, mid, idx, val);
else
update(node * 2 + 2, mid + 1, end, idx, val);
seg[node] = seg[node * 2 + 1] + seg[node * 2 + 2];
}
int qry(int node, int start, int end, int l, int r)
{
if (start > r || end < l)
return 0;
if (start >= l && end <= r)
return seg[node];
int mid = start + (end - start) / 2;
return qry(node * 2 + 1, start, mid, l, r) + qry(node * 2 + 2, mid + 1, end, l, r);
}
void dfs(int u, int par = -1)
{
st[u] = tim++;
for (auto it : adj[u])
{
if (it[0] ^ par)
{
edg[it[2]] = it[0];
dfs(it[0], u);
}
}
en[u] = tim++;
}
ll dfs_qry(int u, int block, int par)
{
if (shop[u])
return 0;
ll answer = INF;
for (auto it : adj[u])
{
if (it[0] ^ par && block != it[2])
{
answer = min(answer, dfs_qry(it[0], block, u) + it[1]);
}
}
return answer;
}
void solve()
{
int n, s, q, e, u, v, w;
cin >> n >> s >> q >> e;
for (int i = 0; i < n - 1; ++i)
{
cin >> u >> v >> w;
adj[u].push_back({v, w, i});
adj[v].push_back({u, w, i});
}
dfs(e);
while (s--)
{
cin >> u;
shop[u] = 1;
}
while (q--)
{
cin >> e >> u;
--e;
update(0, 0, tim, st[edg[e]], 1);
update(0, 0, tim, en[edg[e]], -1);
if (qry(0, 0, tim, 0, st[u]) == 0)
cout << "escaped\n";
else
{
ll answer = dfs_qry(u, e, -1);
if (answer >= INF)
cout << "oo\n";
else
cout << answer << '\n';
}
update(0, 0, tim, st[edg[e]], 0);
update(0, 0, tim, en[edg[e]], 0);
}
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
solve();
return 0;
}
