#include <iostream>
#include <vector>
#include <cmath>
#define inline inline __attribute__((always_inline))
using namespace std;
constexpr int N = 1e5 + 5;
constexpr int logN = static_cast<int>(log2(N));
constexpr long long INF = 1e18;
pair<int, int> edges[N];
vector<pair<int, int>> tree[N];
int timer;
int tin[N], tout[N];
bool special[N];
long long dist[N];
long long down[N];
long long updown[N];
pair<int, long long> up[N][logN + 1];
int tour[N * 2];
void dfs(int u, int p, long long d) {
tin[u] = ++timer;
dist[u] = d;
long long mindown = special[u] ? d : INF;
for (auto [v, w] : tree[u]) {
if (v == p) continue;
dfs(v, u, d + w);
updown[v] = mindown;
mindown = min(mindown, down[v]);
}
mindown = special[u] ? d : INF;
for (auto it = tree[u].rbegin(); it != tree[u].rend(); ++it) {
int v = it->first;
if (v == p) continue;
updown[v] = min(updown[v], mindown);
mindown = min(mindown, down[v]);
}
down[u] = mindown;
tout[u] = timer;
}
void build(int u, int p) {
up[u][0] = {p, updown[u] - 2 * dist[p]};
for (int i = 0; i < logN; i++) {
up[u][i + 1].first = up[up[u][i].first][i].first;
up[u][i + 1].second = min(up[u][i].second, up[up[u][i].first][i].second);
}
for (auto [v, w] : tree[u]) {
if (v == p) continue;
build(v, u);
}
}
signed main()
{
ios::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
// freopen("input.txt", "r", stdin);
int n, k, q, r;
cin >> n >> k >> q >> r;
for (int e = 1; e < n; e++) {
auto &[u, v] = edges[e];
cin >> u >> v;
int w;
cin >> w;
tree[u].emplace_back(v, w);
tree[v].emplace_back(u, w);
}
while (k--) {
int u;
cin >> u;
special[u] = true;
}
dfs(r, r, 0);
build(r, r);
for (int e = 1; e < n; e++) {
auto [u, v] = edges[e];
edges[e] = {max(tin[u], tin[v]), min(tout[u], tout[v])};
}
while (q--) {
int e, u;
cin >> e >> u;
auto [l, r] = edges[e];
if (tin[u] < l || tin[u] > r) {
cout << "escaped\n";
continue;
}
if (special[u]) {
cout << "0\n";
continue;
}
long long res = INF;
for (int i = logN, v = u; i >= 0; i--) {
if (tin[up[v][i].first] < l) continue;
res = min(res, up[v][i].second);
v = up[v][i].first;
}
res = min(res + dist[u], down[u] - dist[u]);
if (res > INF / 2) {
cout << "oo\n";
} else {
cout << res << '\n';
}
}
}
