//#pragma GCC optimize("Ofast", "unroll-loops")
//#pragma GCC target("sse", "sse2", "sse3", "ssse3", "sse4")
#ifdef __APPLE__
#include <iostream>
#include <cmath>
#include <algorithm>
#include <cstdio>
#include <cstdint>
#include <cstring>
#include <string>
#include <cstdlib>
#include <vector>
#include <bitset>
#include <map>
#include <queue>
#include <ctime>
#include <stack>
#include <set>
#include <list>
#include <random>
#include <deque>
#include <functional>
#include <iomanip>
#include <sstream>
#include <fstream>
#include <complex>
#include <numeric>
#include <immintrin.h>
#include <cassert>
#include <array>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <thread>
#else
#include <bits/stdc++.h>
#endif
#define all(a) a.begin(),a.end()
#define len(a) (int)(a.size())
#define mp make_pair
#define pb push_back
#define fir first
#define sec second
#define fi first
#define se second
using namespace std;
typedef pair<int, int> pii;
typedef long long ll;
typedef long double ld;
template<typename T>
bool umin(T &a, T b) {
if (b < a) {
a = b;
return true;
}
return false;
}
template<typename T>
bool umax(T &a, T b) {
if (a < b) {
a = b;
return true;
}
return false;
}
#if __APPLE__
#define D for (bool _FLAG = true; _FLAG; _FLAG = false)
#define LOG(...) print(#__VA_ARGS__" ::", __VA_ARGS__) << endl
template<class ...Ts>
auto &print(Ts ...ts) { return ((cerr << ts << " "), ...); }
#else
#define D while (false)
#define LOG(...)
#endif
//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define int long long
const int maxn = 1e5 + 42, maxk = 22;
int n, s, q, e;
int timer = 0, tin[maxn], tout[maxn];
int dep[maxn], len[maxn], kek[maxn];
bool shop[maxn];
vector<pair<int, int> > g[maxn];
int up[maxn][maxk];
ll upkek[maxn][maxk];
void dfs(int v, int p) {
up[v][0] = p;
tin[v] = timer++;
if(shop[v]) kek[v] = len[v];
else kek[v] = 1e18;
for(auto& to : g[v])
if(to.fi != p) {
dep[to.fi] = dep[v] + 1;
len[to.fi] = len[v] + to.se;
dfs(to.fi, v);
umin(kek[v], kek[to.fi]);
}
tout[v] = timer++;
}
ll get(int v, int to) {
int dist = dep[to] - dep[v];
ll res = kek[v];
int cr = v;
for(int k = 0; k < maxk; k++)
if(((dist >> k) & 1)) {
umin(res, upkek[cr][k]);
cr = up[cr][k];
}
return res + len[v];
}
void solve() {
cin >> n >> s >> q >> e; e--;
vector<pair<int, int> > edg;
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});
edg.pb({v, u});
}
for(int i = 0; i < s; i++) {
int x; cin >> x; shop[--x] = true;
}
dfs(e, e);
for(int i = 0; i < n; i++) {
kek[i] -= len[i] * 2;
upkek[i][0] = kek[i];
}
for(int k = 1; k < maxk; k++)
for(int i = 0; i < n; i++) {
up[i][k] = up[up[i][k - 1]][k - 1];
upkek[i][k] = min(upkek[i][k - 1], upkek[up[i][k - 1]][k - 1]);
}
while(q--) {
int i, v;
cin >> i >> v;
i--; v--;
int to = (dep[edg[i].fi] > dep[edg[i].se] ? edg[i].fi : edg[i].se);
if(tin[to] <= tin[v] && tout[to] >= tout[v]) {
ll cur = get(v, to);
if(cur > (ll)1e14) cout << "oo\n";
else cout << cur << '\n';
} else cout << "escaped\n";
}
}
signed main() {
// freopen("input.txt", "r", stdin);
// freopen("output.txt", "w", stdout);
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t = 1;
//cin >> t;
while (t--) solve();
}
/*
KIVI
*/
