#include <iostream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <functional>
#include <numeric>
#include <cstring>
#include <string>
#include <cmath>
#include <vector>
#include <queue>
#include <stack>
#include <set>
#include <map>
using namespace std;
#define ll long long
#define ull unsigned long long
#define f first
#define s second
#define PF push_front
#define PB push_back
#define MP make_pair
#define max(a, b) ((a > b)? a : b)
#define min(a, b) ((a < b)? a : b)
#define max3(a, b, c) max(max(a, b), c)
#define min3(a, b, c) min(min(a, b), c)
const int N = 1e5 + 5;
const int M = 1e9 + 7;
const int inf = 0x3f3f3f3f;
const ll int INF = 1e18;
vector<vector<pair<int, ll>>> adj(N, vector<pair<int, ll>>()), par(20, vector<pair<int, ll>>(N));
vector<pair<int, int>> edge;
vector<int> depth(N), tin(N), sz(N, 1), to(N);
vector<ll> path(N), dp(N);
vector<bool> isShop(N, false);
int entry = 1;
void dfs(int cur, int prev = -1){
tin[cur] = entry++;
dp[cur] = (isShop[cur])? path[cur] : INF;
for(auto [child, weight] : adj[cur]){
if(child == prev) continue;
depth[child] = depth[cur] + 1;
path[child] = path[cur] + weight;
to[child] = cur;
dfs(child, cur);
if(dp[child] != INF) dp[cur] = min(dp[cur], dp[child] + 2*path[child]);
sz[cur] += sz[child];
}
if(dp[cur] != INF) dp[cur] -= 2*path[cur];
}
bool isAncestor(int child, int anc){
return (tin[anc] <= tin[child] && tin[anc] + sz[anc] > tin[child]);
}
int main(){
ios::sync_with_stdio(false);
cin.tie(NULL);
// ifstream cin();
// ofstream cout();
int n, s, q, e;
cin >> n >> s >> q >> e;
for(int i = 0; i < n-1; i++){
int a, b, w;
cin >> a >> b >> w;
edge.PB(MP(a, b));
adj[a].PB(MP(b, w));
adj[b].PB(MP(a, w));
}
for(int i = 0; i < s; i++) {
int shop;
cin >> shop;
isShop[shop] = true;
}
// let lca(u, v) = w,
// dis(u, v) = path[u] - path[w] + path[v] - path[w]
// let v be the closest shop to w in subtree with root w
// dp[w] = path[v] - 2*path[w];
// Transition: dp[w] = min(dp[i] + 2*path[i]) - 2*path[w];
// Find all dp[i], such that answer for R is path[R] + min(dp[i])
to[e] = e;
path[e] = 0;
dfs(e);
for(int i = 1; i <= n; i++) par[0][i] = MP(to[i], min(dp[i], dp[to[i]]));
for(int i = 1; i < 20; i++){
for(int j = 1; j <= n; j++){
par[i][j] = par[i-1][par[i-1][j].f];
par[i][j].s = min(par[i][j].s, par[i-1][j].s);
}
}
while(q--){
int block, start;
cin >> block >> start;
auto [x, y] = edge[block-1];
if(depth[x] > depth[y]) swap(x, y);
if(isAncestor(start, y)){
int dis = depth[start] - depth[y];
ll mn = INF;
int cur = start;
for(int i = 0; i < 20; i++){
if((dis >> i) & 1){
mn = min(mn, par[i][cur].s);
cur = par[i][cur].f;
}
}
if(mn == INF){
cout << "oo" << endl;
}else {
cout << path[start] + mn << endl;
}
}else {
cout << "escaped" << endl;
}
}
}
