/*#pragma GCC optimize("O3")
#pragma GCC target ("avx2")
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize("unroll-loops")*/
#include <bits/stdc++.h>
#define file(data) freopen(data".in", "r", stdin); freopen(data".out", "w", stdout);
#define pb push_back
#define all(data) data.begin(), data.end()
#define endl '\n'
#define ll long long
//#define int long long
#define pii pair < int, int >
using namespace std;
const int N = 2e5 + 5;
int n, s, q, e, a[N], b[N], w[N], block, deep[N], tin[N], tout[N];
bool shop[N], escape;
vector < pair < int, int > > g[N];
long long ans;
void found(int v, long long sum, int pr) {
if(shop[v]) {
ans = min(sum, ans);
}
if(v == e) {
escape = 1;
return;
}
for(int i = 0; i < g[v].size(); i++) {
int to = g[v][i].first, len = g[v][i].second;
if(to != pr) {
if((a[block] == v && b[block] == to) || (a[block] == to && b[block] == v)) {
continue;
}
found(to, sum + len, v);
}
}
}
int sz;
void dfs(int v, int pr) {
tin[v] = ++sz;
for(int i = 0; i < g[v].size(); i++) {
int to = g[v][i].first;
if(to != pr) {
deep[to] = deep[v] + 1;
dfs(to, v);
}
}
tout[v] = sz;
}
bool upper(int aa, int bb) {
return tin[aa] <= tin[bb] && tout[aa] >= tout[bb];
}
main() {
//file("pieaters");
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n >> s >> q >> e;
for(int i = 1; i < n; i++) {
cin >> a[i] >> b[i] >> w[i];
g[a[i]].pb({b[i], w[i]});
g[b[i]].pb({a[i], w[i]});
}
for(int i = 1; i <= s; i++) {
int x; cin >> x;
shop[x] = 1;
}
if(s == n) {
dfs(e, e);
while(q--) {
int start;
cin >> block >> start;
if(deep[a[block]] > deep[b[block]]) swap(a[block], b[block]);
if(upper(b[block], start)) {
cout << "0\n";
} else {
cout << "escaped\n";
}
}
return 0;
}
while(q--) {
int start;
cin >> block >> start;
escape = 0; ans = 1e14 + 1;
found(start, 0, start);
if(escape) {
cout << "escaped\n";
} else if(ans == 1e14 + 1) {
cout << "oo\n";
} else {
cout << ans << endl;
}
}
}
