#include <bits/stdc++.h>
// Author: Kazuki_Will_Win_VOI_8703
#define fi first
#define se second
#define pii pair<int, int>
#define int long long
#define all(a) a.begin(), a.end()
using namespace std;
const int mn = 2e5 + 5, B = 450, nB = 3005, lg2 = 20, mbit = (1 << 20) + 1, mm = 5e3 + 5, mod = 1e6 + 3, inf = 1e18;
int n, s, q, e, st[mn], ft[mn], up[mn][20], min_val[mn][20], id[mn], d[mn], h[mn], timer = 0, dp[mn];
vector <pii> a[mn];
void pre_dfs(int u, int p){
st[u] = ++ timer;
for(auto [v, w] : a[u]){
if(v == p) continue;
up[v][0] = u;
h[v] = h[u] + 1, d[v] = d[u] + w;
pre_dfs(v, u);
dp[u] = min(dp[u], dp[v] + w);
}
if(id[u]) dp[u] = 0;
ft[u] = timer;
}
void build(){
for(int v = 1; v <= n; v++) min_val[v][0] = dp[v] - d[v];
for(int i = 1; i <= 16; i++){
for(int v = 1; v <= n; v++){
if(up[v][i - 1] != -1){
up[v][i] = up[up[v][i - 1]][i - 1];
}
min_val[v][i] = min(min_val[up[v][i - 1]][i - 1], min_val[v][i - 1]);
}
}
}
int lca(int u, int v){
if(h[u] < h[v]) swap(u, v);
int kc = h[u] - h[v];
for(int i = 16; i >= 0; i--){
if(kc & (1 << i)) u = up[u][i];
}
if(u == v) return u;
for(int i = 16; i >= 0; i--){
if(up[u][i] != -1 && up[v][i] != -1 && up[u][i] != up[v][i]){
u = up[u][i];
v = up[v][i];
}
}
return up[u][0];
}
int get(int u, int v){
int ans = inf;
for(int i = 16; i >= 0; i--){
if(up[u][i] != -1 && h[up[u][i]] >= h[v]){
// cout << i << ' ' << u << ' ' << min_val[u][i] << '\n';
ans = min(ans, min_val[u][i]);
u = up[u][i];
}
}
return ans;
}
pii edge[mn];
void solve(){
cin >> n >> s >> q >> e;
for(int i = 1; i < n; i++){
int u, v, w; cin >> u >> v >> w;
edge[i] = {u, v};
a[u].push_back({v, w});
a[v].push_back({u, w});
}
memset(up, -1, sizeof(up));
fill(dp, dp + mn, inf);
fill(&min_val[0][0], &min_val[0][0] + mn * 20, inf);
for(int i = 1; i <= s; i++){
int u; cin >> u;
id[u] = 1;
}
pre_dfs(e, 0);
build();
// cout << d[5] << '\n';
for(int i = 1; i < n; i++){
auto [u, v] = edge[i];
if(up[v][0] == u) swap(edge[i].fi, edge[i].se);
}
while(q--){
int i, r; cin >> i >> r;
auto [u, v] = edge[i];
if(lca(u, r) != u) cout << "escaped\n";
else{
int ans = min(inf, get(r, v) + d[r]);
if(ans == inf) cout << "oo\n";
else cout << ans << '\n';
}
}
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
int t = 1;
// cin >> t;
while(t--) solve();
}
