#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pii pair<int, int>
#define fi first
#define se second
const int maxn = 1e5 + 10;
int a[maxn], h[maxn], tin[maxn], out[maxn], sz[maxn];
bool check[maxn];
pair<int, pair<int, int>> edge[maxn];
vector<pair<int, int>> g[maxn];
int timeDfs = 0;
struct Node {
int len, mn, par;
} f[maxn][20];
void dfs(int u, int p){
tin[u] = ++timeDfs;
if (check[u]) sz[u] = 1;
else f[u][0].mn = 1e18;
for (auto [v, w]: g[u]){
if (v == p) continue;
h[v] = h[u] + 1;
f[v][0].par = u;
f[v][0].len = w;
dfs(v, u);
sz[u] += sz[v];
f[u][0].mn = min(f[u][0].mn, f[v][0].mn + w);
}
out[u] = timeDfs;
}
void solve(){
int n, s, q, root; cin >> n >> s >> q >> root;
for(int i = 1; i <= n - 1; i++){
int u, v, w; cin >> u >> v >> w;
edge[i] = {u, {v, w}};
g[u].push_back({v, w});
g[v].push_back({u, w});
}
for(int i = 1; i <= s; i++){
cin >> a[i];
check[a[i]] = true;
}
dfs(root, -1);
for(int j = 1; j <= 19; j++){
for(int i = 1; i <= n; i++){
f[i][j].par = f[f[i][j - 1].par][j - 1].par;
f[i][j].len = f[i][j - 1].len + f[f[i][j - 1].par][j - 1].len;
f[i][j].mn = min(f[i][j - 1].mn, f[f[i][j - 1].par][j - 1].mn + f[i][j - 1].len);
}
}
while (q--){
int id, r; cin >> id >> r;
int u = edge[id].fi, v = edge[id].se.fi;
if (h[u] > h[v]) swap(u, v);
if (tin[v] <= tin[r] && out[r] <= out[v]){
if (!sz[v]) cout << "oo" << "\n";
else {
int len = 0, ans = 1e18;
for(int i = log2(n); i >= 0; i--){
if (h[f[r][i].par] >= h[v]){
ans = min(ans, f[r][i].mn + len);
len += f[r][i].len;
r = f[r][i].par;
}
}
cout << min(ans, f[r][0].mn + len) << "\n";
}
}
else cout << "escaped\n";
}
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
solve();
}
