#include <bits/stdc++.h>
typedef long long ll;
const ll inf = 1e15;
struct Edge {
ll u, v, w;
};
int main() {
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr);
ll n, s, q, e;
std::cin >> n >> s >> q >> e;
std::vector<std::vector<std::pair<ll, ll>>> adj(n + 1);
std::vector<Edge> edges;
for (ll i = 0, u, v, w; i < n - 1; ++i) {
std::cin >> u >> v >> w;
adj[u].push_back({v, w});
adj[v].push_back({u, w});
edges.push_back({u, v, w});
}
std::vector<ll> d(n + 1), depth(n + 1);
std::function<void(ll, ll)> dfs;
std::vector<ll> start(n + 1), end(n + 1);
ll timer = 0;
std::vector<std::vector<ll>> lift(n + 1, std::vector<ll>(20));
dfs = [&](ll node, ll par) {
start[node] = timer++;
for (auto &[i, wt] : adj[node]) {
if (i == par) {
continue;
}
lift[i][0] = node;
d[i] = d[node] + wt;
depth[i] = depth[node] + 1;
dfs(i, node);
}
end[node] = timer - 1;
};
lift[e][0] = e;
dfs(e, 0);
std::vector<bool> shop(n + 1);
for (ll i = 0, v; i < s; ++i) {
std::cin >> v;
shop[v] = true;
}
// dp[i] = - 2 * d[i] + min{d[x] forall shop[x] == true, x is in the subtree
// of i}
std::vector<ll> dp(n + 1);
std::function<void(ll, ll)> dfs2;
dfs2 = [&](ll node, ll par) {
if (shop[node]) {
dp[node] = d[node];
} else {
dp[node] = inf;
}
for (auto &[i, wt] : adj[node]) {
if (i == par) {
continue;
}
dfs2(i, node);
dp[node] = std::min(dp[node], dp[i]);
}
};
dfs2(e, 0);
for (ll i = 1; i <= n; ++i) {
if (dp[i] != inf) {
dp[i] -= 2 * d[i];
}
}
std::vector<std::vector<ll>> lmin(n + 1, std::vector<ll>(20));
for (ll i = 1; i <= n; ++i) {
lmin[i][0] = dp[i];
}
for (ll bt = 1; bt < 20; ++bt) {
for (ll i = 1; i <= n; ++i) {
lmin[i][bt] = std::min(lmin[i][bt - 1], lmin[lift[i][bt - 1]][bt - 1]);
lift[i][bt] = lift[lift[i][bt - 1]][bt - 1];
}
}
auto binary_lift = [&](ll x, ll c) {
ll ans = inf;
for (ll bt = 0; bt < 20; ++bt) {
if (c & (1 << bt)) {
ans = std::min(ans, lmin[x][bt]);
x = lift[x][bt];
}
}
return ans;
};
while (q--) {
ll i, r;
std::cin >> i >> r;
--i;
auto [u, v, wt] = edges[i];
if (d[u] > d[v]) {
std::swap(u, v);
}
if (!(start[v] <= start[r] and start[r] <= end[v])) {
std::cout << "escaped\n";
continue;
}
ll val = binary_lift(r, depth[r] - depth[v] + 1);
if (val == inf) {
std::cout << "oo\n";
} else {
std::cout << val + d[r] << '\n';
}
}
}
