#include <bits/stdc++.h>
using namespace std;
vector<vector<pair<unsigned, uint64_t>>> g;
vector<unsigned> height;
vector<bool> is_shop;
vector<uint64_t> parent_dis, subtree_shop_dis;
vector<vector<unsigned>> anc;
void trav(unsigned u, vector<unsigned> &path, unsigned p = -1, unsigned h = 0)
{
height[u] = h;
subtree_shop_dis[u] = UINT64_MAX;
for (size_t i = 1; i <= path.size(); i <<= 1)
anc[u].push_back(path[path.size() - i]);
path.push_back(u);
for (auto const &[v, w] : g[u])
{
if (v != p)
{
trav(v, path, u, h + 1);
if (subtree_shop_dis[v] != UINT64_MAX)
subtree_shop_dis[u] =
min(subtree_shop_dis[u], subtree_shop_dis[v] + w);
parent_dis[v] = w;
}
}
path.pop_back();
if (is_shop[u])
subtree_shop_dis[u] = 0;
}
unsigned lift(unsigned u, unsigned h)
{
size_t z = 0;
while (h)
{
if (h & 1)
u = anc[u][z];
z++;
h >>= 1;
}
return u;
}
size_t lg(size_t n)
{
return 32 - __builtin_clz(n);
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
size_t n, s, q, e;
cin >> n >> s >> q >> e;
e--;
g = vector<vector<pair<unsigned, uint64_t>>>(n);
vector<pair<unsigned, unsigned>> edges;
for (size_t i = 0; i < n - 1; i++)
{
unsigned u, v;
uint64_t w;
cin >> u >> v >> w;
g[u - 1].emplace_back(v - 1, w);
g[v - 1].emplace_back(u - 1, w);
edges.emplace_back(u - 1, v - 1);
}
is_shop = vector<bool>(n, 0);
for (size_t i = 0; i < s; i++)
{
unsigned j;
cin >> j;
is_shop[j - 1] = 1;
}
height = vector<unsigned>(n);
parent_dis = vector<uint64_t>(n);
subtree_shop_dis = vector<uint64_t>(n, UINT64_MAX);
anc = vector<vector<unsigned>>(n);
vector<unsigned> path;
trav(e, path);
vector<vector<uint64_t>> shop_dis(n), dis(n);
for (size_t i = 0; i < n; i++)
{
if (i != e)
{
shop_dis[i].push_back(subtree_shop_dis[i]);
if (subtree_shop_dis[anc[i][0]] != UINT64_MAX)
shop_dis[i].back() =
min(shop_dis[i].back(), parent_dis[i] + subtree_shop_dis[anc[i][0]]);
dis[i].push_back(parent_dis[i]);
}
}
for (size_t j = 1; j < lg(n); j++)
for (size_t i = 0; i < n; i++)
if (j < anc[i].size())
{
shop_dis[i].push_back(shop_dis[i][j - 1]);
if (shop_dis[anc[i][j - 1]][j - 1] != UINT64_MAX)
shop_dis[i].back() =
min(shop_dis[i].back(),
shop_dis[anc[i][j - 1]][j - 1] + dis[i][j - 1]);
dis[i].push_back(dis[i][j - 1] + dis[anc[i][j - 1]][j - 1]);
}
for (size_t i = 0; i < q; i++)
{
size_t j, r;
cin >> j >> r;
j--, r--;
auto [u, v] = edges[j];
if (height[u] > height[v])
swap(u, v);
if (height[u] >= height[r])
{
cout << "escaped\n";
continue;
}
if (lift(r, height[r] - height[v]) == v)
{
size_t h = height[r] - height[v], z = 0;
uint64_t d = 0, min_shop_d = UINT64_MAX;
while (h)
{
if (h & 1)
{
min_shop_d = min(min_shop_d, shop_dis[r][z] + d);
d += dis[r][z];
r = anc[r][z];
}
h >>= 1;
z++;
}
if (min_shop_d == UINT64_MAX)
cout << "oo\n";
else
cout << min_shop_d << '\n';
}
else
{
cout << "escaped\n";
continue;
}
}
}
