#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
const int LOG = 20;
int n, s, q, e, timer = 0;
vector<vector<pii> > graph;
vector<int> store, in, out, depth, par;
vector<vector<int> > up;
vector<ll> dp, dist;
vector<vector<ll> > mn;
void dfs(int u, int p) {
in[u] = timer++;
if(store[u]) dp[u] = dist[u];
else dp[u] = 1e17;
for(auto &[v, w] : graph[u]) {
if(v == p) continue;
dist[v] = dist[u] + w;
par[v] = u;
dfs(v, u);
dp[u] = min(dp[u], dp[v]);
}
out[u] = timer;
}
void dfs2(int u, int p) {
for(int i=1; i<LOG; i++) {
up[u][i] = up[ up[u][i-1] ][i-1];
mn[u][i] = min(mn[u][i-1], mn[ up[u][i-1] ][i-1]);
}
for(auto &[v, _] : graph[u]) {
if(v == p) continue;
up[v][0] = u;
mn[v][0] = dp[u];
dfs2(v, u);
}
}
bool anc(int u, int v) { return (in[u] <= in[v] && out[u] >= out[v]); }
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin >> n >> s >> q >> e;
graph.resize(n+1);
par.resize(n+1);
in.resize(n+1);
out.resize(n+1);
store.resize(n+1);
dist.resize(n+1);
depth.resize(n+1);
up.resize(n+1, vector<int>(LOG));
dp.resize(n+1, 1e18);
mn.resize(n+1, vector<ll>(LOG, 1e18));
vector<pii> edges;
for(int i=0; i<n-1; i++) {
int a, b, w;
cin >> a >> b >> w;
edges.push_back({ a, b });
graph[a].push_back({ b, w });
graph[b].push_back({ a, w });
}
for(int i=0; i<s; i++) {
int x;
cin >> x;
store[x] = 1;
}
dfs(e, 0);
for(int u=1; u<=n; u++) dp[u] -= 2 * dist[u];
dfs2(e, 0);
for(pii &e : edges)
if(in[e.first] < in[e.second]) swap(e.first, e.second);
while(q--) {
int I, R;
cin >> I >> R;
pii edge = edges[I-1];
if(anc(edge.first, R) == anc(edge.first, e)) {
cout << "escaped\n";
continue;
}
ll ans = dp[R] + dist[R];
int u = R;
for(int j=LOG-1; j>=0; j--) {
if(up[u][j] == 0) continue;
if(!anc(edge.first, up[u][j])) continue;
ans = min(ans, dist[R] + mn[u][j]);
u = up[u][j];
}
if(ans >= 1e15) cout << "oo\n";
else cout << ans << '\n';
}
return 0;
}
