/*
#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx2,fma,bmi,bmi2,sse4.2,popcnt,lzcnt")
*/
#include <bits/stdc++.h>
#define taskname ""
#define all(x) x.begin(), x.end()
#define ll long long
#define ld long double
#define pb push_back
#define ff first
#define ss second
#define pii pair<int, int>
#define vi vector<int>
using namespace std;
const int mxN = 1e5 + 5;
const int mod = 1e9 + 7;
const int lim = 17;
const ll oo = 1e18;
vector<pii> G[mxN];
bool shop[mxN];
int n, s, q, root, par[lim][mxN];
int tin[mxN], tout[mxN], timer;
vector<pii> edges;
ll dp[lim][mxN], dep[mxN];
void dfs(int v, int p) {
tin[v] = ++timer;
ll cur = oo;
par[0][v] = p;
if(shop[v])
cur = dep[v];
for(pii tmp : G[v]) {
int u = tmp.ff, w = tmp.ss;
if(u == p)
continue;
dep[u] = dep[v] + w;
dfs(u, v);
cur = min(cur, dp[0][u]);
}
dp[0][v] = cur;
// cout << "0 " << v << ' ' << cur << endl;
tout[v] = timer;
}
bool is_ancestor(int v, int u) {
if(v == 0)
return true;
return (tin[v] <= tin[u] && tout[v] >= tout[u]);
}
int find_lca(int v, int u) {
if(is_ancestor(v, u))
return v;
if(is_ancestor(u, v))
return u;
for(int i = lim - 1; i >= 0; --i)
if(!is_ancestor(par[i][v], u))
v = par[i][v];
return par[0][v];
}
void solve() {
cin >> n >> s >> q >> root;
for(int i = 1; i < n; ++i) {
int u, v, w;
cin >> u >> v >> w;
G[u].pb({v, w});
G[v].pb({u, w});
edges.pb({u, v});
}
for(int i = 1; i <= s; ++i) {
int tmp; cin >> tmp;
shop[tmp] = true;
}
dfs(root, 0);
for(int i = 1; i <= n; ++i)
if(dp[0][i] != oo)
dp[0][i] -= 2 * dep[i];
for(int i = 1; i < lim; ++i) {
for(int j = 1; j <= n; ++j) {
par[i][j] = par[i - 1][par[i - 1][j]];
dp[i][j] = min(dp[i - 1][j], dp[i - 1][par[i - 1][j]]);
// cout << i << " " << j << " " << dp[i][j] << endl;
}
}
while(q--) {
int idx, st;
cin >> idx >> st;
--idx;
if(edges[idx].ss == par[0][edges[idx].ff])
swap(edges[idx].ff, edges[idx].ss);
if(is_ancestor(edges[idx].ss, st)) {
ll res = oo;
int ori_st = st;
for(int i = lim - 1; i >= 0; --i) {
if(is_ancestor(edges[idx].ss, par[i][st])) {
res = min(res, dp[i][st]);
// cout << i << " " << st << endl;
st = par[i][st];
}
}
res = min(res, dp[0][st]);
if(res == oo)
cout << "oo\n";
else
cout << res + dep[ori_st] << "\n";
}
else
cout << "escaped\n";
}
}
signed main() {
#ifndef CDuongg
if(fopen(taskname".inp", "r"))
assert(freopen(taskname".inp", "r", stdin)), assert(freopen(taskname".out", "w", stdout));
#else
freopen("bai3.inp", "r", stdin);
freopen("bai3.out", "w", stdout);
auto start = chrono::high_resolution_clock::now();
#endif
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int t = 1; //cin >> t;
while(t--) solve();
#ifdef CDuongg
auto end = chrono::high_resolution_clock::now();
cout << "\n"; for(int i = 1; i <= 100; ++i) cout << '=';
cout << "\nExecution time: " << chrono::duration_cast<chrono::milliseconds> (end - start).count() << "[ms]" << endl;
#endif
}
