// 23 - 12 - 23
#include<bits/stdc++.h>
using namespace std;
#define read() ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define day() time_t now = time(0);char* x = ctime(&now);cerr<<"Right Now Is : "<<x<<"\n"
#define int long long
#define ii pair<int,int>
#define X first
#define Y second
const long long MAX = (int)1e5 + 5;
const long long INF = (int)1e15;
const long long MOD = (int)1e9 + 7;
int n,s,q,ew;
struct node{
int u,v,w;
}a[MAX];
bool food[MAX];
vector<ii> qrx[MAX];
int in[MAX],out[MAX],times,h[MAX];
vector<ii> adj[MAX];
int st[MAX << 2],lazy[MAX << 2];
int res[MAX];
void lazu(int id = 1,int l = 1,int r = n){
if(!lazy[id])return;
st[id] += lazy[id];
if(l != r){
lazy[id << 1] += lazy[id];
lazy[id << 1 | 1] += lazy[id];
}
lazy[id] = 0;
}
void update(int u,int v,int val,int id = 1,int l = 1,int r = n){
if(u > v)return;
if(u > r || v < l)return;
if(u <= l && r <= v){
lazy[id] += val;
lazu(id,l,r);
return;
}
lazu(id,l,r);
int m = l + r >> 1;
update(u,v,val,id << 1,l,m);
update(u,v,val,id << 1 | 1,m + 1,r);
st[id] = min(st[id << 1],st[id << 1 | 1]);
}
int get(int u,int v,int id = 1,int l = 1,int r = n){
if(u > r || v < l)return INF;
lazu(id,l,r);
if(u <= l && r <= v)return st[id];
int m = l + r >> 1;
return min(get(u,v,id << 1,l,m),get(u,v,id << 1 | 1,m + 1,r));
}
void dfs(int u = 1,int p = 0){
in[u] = ++times;
for(auto e : adj[u]){
int v = e.X;
int w = e.Y;
if(v == p)continue;
h[v] = h[u] + w;
dfs(v,u);
}
out[u] = times;
}
void calc(int u = 1,int p = 0){
for(auto e : qrx[u]){
int id = e.Y;
int tv = e.X;
int u_ = a[tv].u;
int v_ = a[tv].v;
if(in[u_] > in[v_])swap(u_,v_);
if(in[v_] <= in[u] && out[v_] >= in[u]){
if(in[v_] <= in[ew] && in[ew] <= out[v_])res[id] = -1;
else res[id] = get(in[v_],out[v_]);
}
else {
if(in[v_] <= in[ew] && in[ew] <= out[v_])
res[id] = min(get(1,in[v_] - 1),get(out[v_] + 1,n));
else
res[id] = -1;
}
}
for(auto e : adj[u]){
int v = e.X;
int w = e.Y;
if(v == p)continue;
update(1,in[v] - 1,w);
update(in[v],out[v],-w);
update(out[v] + 1,n,w);
calc(v,u);
update(1,in[v] - 1,-w);
update(in[v],out[v],+w);
update(out[v] + 1,n,-w);
}
}
signed main(){
read();
times = 0;
cin >> n >> s >> q >> ew;
for(int i = 1,u,v,w;i < n;i++){
cin >> u >> v >> w;
a[i] = {u,v,w};
adj[u].push_back({v,w});
adj[v].push_back({u,w});
}
for(int i = 1,x;i <= s;i++){
cin >> x;
food[x] = 1;
}
dfs();
for(int i = 1,x,r;i <= q;i++){
cin >> x >> r;
qrx[r].push_back({x,i});
}
for(int i = 1;i <= n;i++){
if(food[i])update(in[i],in[i],h[i]);
else update(in[i],in[i],INF + h[i]);
}
calc();
for(int i = 1;i <= q;i++){
if(res[i] >= INF)cout << "oo\n";
else if(res[i] == -1)cout << "escaped\n";
else cout << res[i] << '\n';
}
}
