#include <bits/stdc++.h>
#define int long long
using namespace std;
int n,s,q,e;
int INF = 1LL<<60;
vector<vector<pair<int,int>>> adjlist;
vector<int> dist;
vector<int> dp1;
vector<int> is_shop;
vector<int> parent;
vector<int> depth;
vector<int> blubber;
vector<int> preorder, postorder;
int current = 0;
void dfs(int node, int par) {
//cout << node <<" " << par << endl;
preorder[node] = current;
current++;
for (auto j:adjlist[node]) {
int w = j.second;
int x = j.first;
if (x!=par) {
dist[x] = min(dist[x], dist[node]+w);
depth[x] = depth[node]+1;
parent[x] = node;
dfs(x,node);
dp1[node] = min(dp1[node],dp1[x]+w);
}
}
postorder[node] = current;
current++;
}
signed main() {
/*#ifndef ONLINE_JUDGE
// for getting input from input.txt
freopen("input.txt", "r", stdin);
// for writing output to output.txt
freopen("output.txt", "w", stdout);
#endif*/
/*#ifdef ONLINE_JUDGE
ios_base::sync_with_stdio(false);
cin.tie(NULL);
#endif*/ //fast IO
cin >> n >> s >> q >> e;
e--;
adjlist=vector<vector<pair<int,int>>>(n);
dist=dp1=blubber=vector<int>(n,INF);
is_shop = depth = vector<int>(n,0);
preorder = postorder = parent = vector<int>(n,-1);
vector<pair<int,int>> edges;
for (int i=0; i<n-1; i++) {
int a,b,w;
cin >> a >> b >> w;
a--;
b--;
//cout << a <<" " << b <<" " << w << " " << adjlist.size() << endl;
adjlist[a].push_back({b,w});
adjlist[b].push_back({a,w});
edges.push_back({a,b});
}
for (int i=0; i<s; i++) {
int x;
cin >> x;
x--;
is_shop[x] = 1;
dp1[x] = 0;
}
dist[e] = 0;
dfs(e,-1);
for (int i=0; i<n; i++) {
if (dp1[i]==INF) {
blubber[i] = INF;
}
else {
blubber[i] = dp1[i]-dist[i];
}
}
int K = 3;
vector<vector<int>> multiparent(n,vector<int>(K,-1));
vector<vector<int>> minima(n,vector<int>(K,INF)); //min value of blubber upto 2^j ancestors
for (int i=0; i<n; i++) {
multiparent[i][0] = parent[i];
minima[i][0] = blubber[i];
}
parent[e] = multiparent[e][0] = e;
cout << endl;
for (int p=1; p<K; p++) {
for (int i=0; i<n; i++) {
//cout << i <<" " << p << " " << multiparent[i][p-1] << endl;
multiparent[i][p] = multiparent[multiparent[i][p-1]][p-1];
minima[i][p] = min(minima[i][p-1], minima[multiparent[i][p-1]][p-1]);
}
}
for (int qu=0; qu<q; qu++) {
int I,R;
cin >> I >> R;
I--;
R--;
int a = edges[I].first;
int b = edges[I].second;
if (depth[a]>depth[b]) {
swap(a,b);
}
//care about b (higher depth)
//if R is not in the subtree of b then it's escaped
//cout << b <<" " << R<<" " << preorder[b] <<" " << preorder[R] << " " << postorder[R] << " " << postorder[b] << endl;
if (!(preorder[b]<=preorder[R] && preorder[R]<=postorder[R] && postorder[R]<=postorder[b])) {
cout << "escaped" << endl;
}
else {
cout << 0 << endl;
}
}
for (int i=0; i<n; i++) {
//cout << i <<" " << preorder[i] <<" " << postorder[i] << endl;
}
/*for (int p=0; p<K; p++) {
cout << "lifting " << p << endl;
for (int i=0; i<n; i++) {
cout << i <<" " << multiparent[i][p] <<" " << minima[i][p] << endl;
}
}
cout << "blubbers" << endl;
for (int i=0; i<n; i++) {
cout << i << " " << dist[i] << " " << dp1[i] << " " << blubber[i] << endl;
}*/
}
