#include <iostream>
#include <vector>
#include <bitset>
using namespace std;
using ll = long long;
const int MAXN = 1e5 + 123;
const ll INF = 1e18 + 177013;
const ll LESSINF = 1e14 + 177013;
vector<pair<int, ll>> edg[MAXN];
vector<pair<int, int>> qrs[MAXN];
bitset<MAXN> shop;
int tin[MAXN];
int tout[MAXN];
ll depth[MAXN];
vector<int> rtin;
int rt[MAXN];
void dfs(int v) {
tin[v] = rtin.size();
rtin.push_back(v);
for (auto [u, w] : edg[v]) {
if (u == rt[v])
continue;
rt[u] = v;
depth[u] = depth[v] + w;
dfs(u);
}
tout[v] = rtin.size();
}
int e;
ll ans_dfs(int v, int urest, int rt0, ll d) {
if (v == e)
return -1;
ll ans = INF;
if (shop[v])
ans = d;
for (auto [u, w] : edg[v]) {
if (u == rt0 || (v == urest && rt[v] == u) || (u == urest && rt[u] == v))
continue;
ans = min(ans, ans_dfs(u, urest, v, d + w));
}
return ans;
}
signed main() {
int n, s, q;
cin >> n >> s >> q >> e;
vector<pair<int, int>> roads(n - 1);
--e;
for (int i = 0; i < n - 1; ++i) {
int u, v, w;
cin >> u >> v >> w;
--u, --v;
edg[u].push_back({v, w});
edg[v].push_back({u, w});
roads[i] = {u, v};
}
for (int i = 0; i < s; ++i) {
int c;
cin >> c;
shop[c - 1] = 1;
}
dfs(0);
for (auto& [ru, rv] : roads) {
if (rt[rv] == ru)
swap(rv, ru);
}
for (int i = 0; i < q; ++i) {
int ri, v;
cin >> ri >> v;
--ri, --v;
int u = roads[ri].first;
ll ans = ans_dfs(v, u, -1, 0);
if (ans == -1) {
cout << "escaped\n";
} else if (ans > LESSINF) {
cout << "oo\n";
} else {
cout << ans << '\n';
}
}
}
