#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int mxN = 1e5+10;
const ll INF = 1e15;
vector<array<int, 2>> adj[mxN];
int anc[mxN][20], d[mxN];
ll magic[mxN][20];
ll dist[mxN], mn[mxN];
bool sp[mxN];
void jmp(int &x, int dist) {
for(int k = 19; k >= 0; k--) {
if(dist & (1 << k)) x = anc[x][k];
}
}
int lca(int a, int b) {
if(d[b] > d[a]) swap(a, b);
jmp(a, d[a]-d[b]);
if(a == b) return a;
for(int k = 19; k >= 0; k--) {
if(anc[a][k] != anc[b][k]) {
a = anc[a][k];
b = anc[b][k];
}
}
return anc[a][0];
}
void dfs(int node, int p, int e) {
anc[node][0] = p;
if(node == e) anc[node][0] = e;
if(sp[node]) mn[node] = dist[node];
for(int k = 1; k <= 19; k++) {
anc[node][k] = anc[anc[node][k-1]][k-1];
}
for(auto [it, w] : adj[node]) {
if(it == p) continue;
d[it] = d[node]+1;
dist[it] = dist[node] + w;
dfs(it, node, e);
mn[node] = min(mn[node], mn[it]);
}
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, s, q, e;
cin >> n >> s >> q >> e;
vector<array<int, 3>> queries;
for(int i = 1; i < n; i++) {
int a, b, w;
cin >> a >> b >> w;
adj[a].push_back({b, w});
adj[b].push_back({a, w});
queries.push_back({a, b, w});
mn[i] = INF;
}
mn[n] = INF;
for(int i = 0; i < s; i++) {
int k;
cin >> k;
sp[k] = true;
}
dfs(e, 0, e);
for(int i = 1; i <= n; i++) {
if(mn[i] != INF) mn[i] = mn[i] - 2 * dist[i];
magic[i][0] = mn[i];
}
for(int k = 1; k <= 19; k++) {
for(int i = 1; i <= n; i++) {
magic[i][k] = min(magic[i][k-1], magic[anc[i][k-1]][k-1]);
}
}
while(q--) {
int idx; int k;
cin >> idx >> k; --idx;
int a = queries[idx][0], b = queries[idx][1];
if(d[b] < d[a]) swap(a, b);
int anc1 = lca(k, b);
if(anc1 != b) {
cout << "escaped\n";
continue;
}
int distance = d[k]-d[b];
ll ans = INF;
int x = k;
for(int k1 = 19; k1 >= 0; k1--) {
if(distance & (1 << k1)) {
ans = min(ans, magic[x][k1]+dist[k]);
x = anc[x][k1];
}
}
ans = min(ans, mn[b]+dist[k]);
if(ans == INF) cout << "oo\n";
else cout << ans << '\n';
}
return 0;
}
