#include <bits/stdc++.h>
using namespace std;
int n, m, q, root;
int in[100010], out[100010], ti, s[100010];
int par[100010][20];
long long rmq[100010][20], d[100010], dmin[100010];
pair <int, int> e[100010];
vector <pair <int, int> > adj[100010];
void dfs(int u, int p) {
in[u] = ++ti;
dmin[u] = (s[u] ? d[u] : 1e18);
par[u][0] = p;
for (int i = 1; i < 20; ++i)
par[u][i] = par[par[u][i - 1]][i - 1];
for (auto [v, w]: adj[u]) {
if (v == p) continue;
d[v] = d[u] + w;
dfs(v, u);
dmin[u] = min(dmin[u], dmin[v]);
}
out[u] = ti;
}
void initrmq(int u, int p) {
rmq[u][0] = dmin[u] - 2 * d[u];
for (int i = 1; i < 20; ++i)
rmq[u][i] = min(rmq[u][i - 1], rmq[par[u][i - 1]][i - 1]);
for (auto [v, w]: adj[u]) {
if (v == p) continue;
initrmq(v, u);
}
}
int check(int u, int v) {
return in[u] <= in[v] && out[v] <= out[u];
}
long long get(int u, int w) {
long long res = rmq[w][0];
for (int i = 19; i >= 0; --i) {
if (par[u][i] && check(w, par[u][i])) {
res = min(res, rmq[u][i]);
u = par[u][i];
}
}
return res;
}
int main() {
ios_base :: sync_with_stdio(false);
cin.tie(0); cout.tie(0);
cin >> n >> m >> q >> root;
for (int i = 1; i < n; ++i) {
int u, v, w;
cin >> u >> v >> w;
adj[u].push_back({v, w});
adj[v].push_back({u, w});
e[i] = {u, v};
}
while (m--) {
int u;
cin >> u;
s[u] = 1;
}
dfs(root, 0);
initrmq(root, 0);
while (q--) {
int u, id;
cin >> id >> u;
int w = (check(e[id].first, e[id].second) ? e[id].second : e[id].first);
if (!check(w, u)) cout << "escaped\n";
else {
long long ans = get(u, w);
if (ans >= 1e16) cout << "oo\n";
else cout << ans + d[u] << "\n";
}
}
}
