#include "bits/stdc++.h"
using namespace std;
#ifdef duc_debug
#include "bits/debug.h"
#else
#define debug(...)
#endif
const int maxn = 1e5 + 5;
const int LG = 18;
int n, s, q, e;
int eu[maxn], ev[maxn], ew[maxn];
vector<pair<int, int>> g[maxn];
bool spec[maxn];
int up[maxn][LG + 1], h[maxn];
long long st[maxn][LG + 1];
long long dep[maxn];
long long f[maxn];
void pre_dfs(int u, int prev) {
f[u] = 1e18;
if (spec[u]) f[u] = 0;
for (auto [v, w] : g[u]) {
if (v == prev) continue;
up[v][0] = u;
for (int i = 1; i <= LG; ++i) {
up[v][i] = up[up[v][i - 1]][i - 1];
}
h[v] = h[u] + 1;
dep[v] = dep[u] + w;
pre_dfs(v, u);
if (f[u] > f[v] + w) {
f[u] = f[v] + w;
}
}
}
int lca(int u, int v) {
if (h[u] < h[v]) swap(u, v);
for (int i = LG; i >= 0; --i) {
if ((h[u] - h[v]) >> i & 1) u = up[u][i];
}
if (u == v) return u;
for (int i = LG; i >= 0; --i) {
if (up[u][i] != up[v][i]) u = up[u][i], v = up[v][i];
}
return up[v][0];
}
long long dist(int u, int v) {
return dep[u] + dep[v] - 2 * dep[lca(u, v)];
}
void solve() {
cin >> n >> s >> q >> e;
for (int i = 1; i < n; ++i) {
int u, v, w; cin >> u >> v >> w;
g[u].emplace_back(v, w);
g[v].emplace_back(u, w);
eu[i] = u, ev[i] = v, ew[i] = w;
}
for (int i = 1; i <= s; ++i) {
int x; cin >> x;
spec[x] = 1;
}
pre_dfs(e, 0);
for (int i = 1; i <= n; ++i) {
st[i][0] = f[up[i][0]] - dep[up[i][0]];
}
for (int i = 1; i <= LG; ++i) {
for (int u = 1; u <= n; ++u) {
st[u][i] = min(st[u][i - 1], st[up[u][i - 1]][i - 1]);
}
}
while (q--) {
int edge, r; cin >> edge >> r;
int pu = eu[edge], pv = ev[edge];
if (up[pu][0] == pv) swap(pu, pv);
if (lca(r, pv) != pv) {
cout << "escaped\n";
continue;
}
int u = r;
long long res = f[u];
for (int i = LG; i >= 0; --i) {
if ((h[u] - h[pv]) >> i & 1) {
res = min(res, dep[r] + st[u][i]);
u = up[u][i];
}
}
if (res == 1e18) {
cout << "oo\n";
} else cout << res << '\n';
}
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
solve();
return 0;
}
