#include <bits/stdc++.h>
#ifdef __LOCAL__
#include <debug_local.h>
#endif
using namespace std;
const int mxN = 1e5 + 5;
const int lg = 20;
const long long inf = 1e18;
vector<tuple<int, int, int>> ad[mxN];
bool on[mxN];
int lower[mxN], level[mxN], in[mxN], out[mxN], timer, par[mxN][lg];
long long dist[mxN], depth[mxN];
long long st[mxN][lg];
void dfs(int u, int p) {
in[u] = ++timer;
if (on[u]) dist[u] = 0;
par[u][0] = p;
for (auto [v, w, i] : ad[u]) {
if (v == p) continue;
lower[i] = v;
depth[v] = depth[u] + w;
level[v] = level[u] + 1;
dfs(v, u);
dist[u] = min(dist[u], dist[v] + w);
}
out[u] = timer;
}
void build_ST_dfs(int u, int p) {
st[u][0] = (dist[u] == inf ? inf : dist[u] - depth[u]);
for (int i = 1; i < lg; i++) {
par[u][i] = par[par[u][i - 1]][i - 1];
st[u][i] = min(st[u][i - 1], st[par[u][i - 1]][i - 1]);
}
for (auto [v, w, i] : ad[u]) {
if (v == p) continue;
build_ST_dfs(v, u);
}
}
void testCase() {
int n, s, q, e;
cin >> n >> s >> q >> e;
for (int i = 1; i <= n; i++) {
dist[i] = inf;
}
for (int i = 0; i < n - 1; i++) {
int u, v, w;
cin >> u >> v >> w;
ad[u].push_back({v, w, i + 1});
ad[v].push_back({u, w, i + 1});
}
for (int i = 0; i < s; i++) {
int u;
cin >> u;
on[u] = 1;
}
dfs(e, e);
build_ST_dfs(e, e);
while (q--) {
int i, r;
cin >> i >> r;
int t = lower[i];
if (in[t] <= in[r] && out[r] <= out[t]) {
long long ans = inf;
int k = level[r] - level[t] + 1;
int init_r = r;
for (int i = lg - 1; i >= 0; i--) {
if (k >> i & 1) ans = min(ans, st[r][i]), r = par[r][i];
}
if (ans == inf) cout << "oo\n";
else cout << ans + depth[init_r] << "\n";
} else {
cout << "escaped\n";
}
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
testCase();
return 0;
}
