#include <algorithm>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#ifdef DEBUG
#include <time.h>
#endif
#define all(a) (a).begin(), (a).end()
#define rev(a) (a).rbegin(), (a).rend()
#define F first
#define S second
int recur_depth = 0;
#ifdef DEBUG
#define dbg(x) \
{ \
++recur_depth; \
auto x_ = x; \
--recur_depth; \
cerr << string(recur_depth, '\t') << "\e[91m" << __func__ << ":" \
<< __LINE__ << "\t" << #x << " = " << x_ << "\e[39m" << endl; \
}
#else
#define dbg(x)
#endif
using namespace std;
using namespace __gnu_pbds;
typedef pair<int, int> ii;
typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> llll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pair<int, int>> vii;
typedef vector<vii> vvii;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<pair<ll, ll>> vll;
typedef vector<vll> vvll;
typedef vector<bool> vb;
template <class type1>
using ordered_set = tree<type1, null_type, less<type1>, rb_tree_tag,
tree_order_statistics_node_update>;
template <typename A, typename B>
ostream &operator<<(ostream &os, const pair<A, B> &p) {
return os << '(' << p.first << ", " << p.second << ')';
}
template <typename T_container, typename T = typename enable_if<
!is_same<T_container, string>::value,
typename T_container::value_type>::type>
ostream &operator<<(ostream &os, const T_container &v) {
os << '{';
string sep;
for (const T &x : v)
os << sep << x, sep = ", ";
return os << '}';
}
const ll MOD = 1e9 + 7;
// const ll MOD = 998244353;
const ll INF = 1e9;
const ld EPS = 1e-9;
void solve() {
int n, s, q, e;
cin >> n >> s >> q >> e;
e--;
vvl eds(n - 1);
vvll adj(n);
for (int i = 0; i < n - 1; i++) {
ll u, v, w;
cin >> u >> v >> w;
u--, v--;
adj[u].push_back({v, w});
adj[v].push_back({u, w});
eds[i] = {u, v, w};
}
vb shops(n);
for (int i = 0; i < s; i++) {
int u;
cin >> u;
shops[--u] = 1;
}
int timer = 0;
vl tin(n), tout(n);
vll par(n, {-1, -1});
function<void(int, int)> f = [&](int u, int p) {
tin[u] = timer++;
for (auto [v, w] : adj[u])
if (v != p) {
par[v] = {u, w};
f(v, u);
}
tout[u] = timer++;
};
f(0, -1);
auto is_anc = [&](int u, int v) {
return tin[u] <= tin[v] && tout[v] <= tout[u];
};
while (q--) {
int i, r;
cin >> i >> r;
i--, r--;
int del_p = eds[i][0], del_u = eds[i][1];
if (del_u == par[del_p].first)
swap(del_p, del_u);
bool escaped = is_anc(del_u, r) == is_anc(del_u, e);
if (escaped) {
cout << "escaped\n";
continue;
}
if (s == n) {
cout << "0\n";
continue;
}
bool flag = 0;
vl dist(n, INF);
vb vis(n);
priority_queue<llll, vll, greater<llll>> pq;
dist[r] = 0;
pq.push({0, r});
while (!pq.empty()) {
auto [d, u] = pq.top();
pq.pop();
if (vis[u])
continue;
vis[u] = 1;
if (shops[u]) {
flag = 1;
cout << d << "\n";
break;
}
for (auto [v, w] : adj[u])
if (!(del_u == u && del_p == v) && !(del_p == u && del_u == v))
if (!vis[v] && dist[v] > d + w) {
dist[v] = d + w;
pq.push({dist[v], v});
}
}
if (!flag)
cout << "oo\n";
}
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(NULL);
clock_t start = clock();
int test_cases = 1;
// cin >> test_cases;
while (test_cases--)
solve();
#ifdef DEBUG
cerr << fixed << setprecision(10)
<< "\nTime Taken: " << (double)(clock() - start) / CLOCKS_PER_SEC
<< "s\n";
#endif
return 0;
}
