#include<bits/stdc++.h>
#define fi first
#define se second
#define pb push_back
using namespace std;
using ll = long long;
using ull = unsigned long long;
template<typename T> bool ckmx(T& a, const T& b){if(a <= b) return a = b, true; return false;}
template<typename T> bool ckmn(T& a, const T& b){if(a >= b) return a = b, true; return false;}
const int N = 1e5+5;
const ll inf = 1e18+1;
const int lg = 21;
int n, q, S, Exit, timerDFS;
int h[N], par[lg][N], tin[N], tout[N];
ll val[lg][N], dist[N], near[N];
bool isShop[N], del[N];
vector<pair<int,ll>> adj[N];
vector<pair<int,ll>> id_adj[N];
pair<int,int> Edge[N];
bool in(int u, int v){
return tin[u] <= tin[v] && tout[v] <= tout[u];
}
void dfs(int x, int p){
tin[x] = ++timerDFS;
near[x] = (isShop[x] ? dist[x] : inf);
for(pair<int,ll> e : adj[x])if(e.fi != p){
int v = e.fi; ll w = e.se;
h[v] = h[x] + 1;
dist[v] = dist[x] + w;
par[0][v] = x;
for(int i = 1; i < lg; i++){
par[i][v] = par[i-1][par[i-1][v]];
}
dfs(v, x);
ckmn(near[x], near[v]);
}
tout[x] = ++timerDFS;
return;
}
ll get(int x, int asc){
int k = h[x] - h[asc]+1; ll res = inf;
for(int i = 0; i < lg; i++){
if(k>>i&1){
ckmn(res, val[i][x]);
x = par[i][x];
}
}
return res;
}
ll BFS(int source){
queue<int> q;
vector<ll> d(n+1, inf);
vector<bool> vis(n+1, false);
d[source] = 0;
vis[source] = true;
q.push(source);
ll answer = inf;
while(!q.empty()){
int x = q.front(); q.pop();
if(isShop[x]){
answer = min(answer, d[x]);
}
for(pair<int,int> e: id_adj[x]){
if(del[e.fi]) continue;
int v = Edge[e.fi].fi ^ Edge[e.fi].se ^ x;
if(vis[v]) continue;
d[v] = d[x] + e.se;
vis[v] = true;
q.push(v);
}
}
return answer;
}
void solve()
{
cin >> n >> S >> q >> Exit;
for(int i = 1; i < n; i++){
int u,v,w; cin >> u >> v >> w;
adj[u].pb(make_pair(v, w));
adj[v].pb(make_pair(u, w));
Edge[i] = make_pair(u, v);
id_adj[u].pb(make_pair(i, w));
id_adj[v].pb(make_pair(i, w));
}
for(int i = 1; i <= S; i++){
int v; cin >> v;
isShop[v] = true;
}
dfs(1, -1);
for(int i = 1; i <= n; i++){
if(near[i] == inf){
val[0][i] = inf;
}
else{
val[0][i] = -2*dist[i] + near[i];
}
}
for(int i = 1; i < lg; i++){
for(int j = 1; j <= n; j++){
val[i][j] = min(val[i-1][j], val[i-1][par[i-1][j]]);
}
}
while(q--){
int i,R; cin >> i >> R;
if(h[Edge[i].fi] > h[Edge[i].se]) swap(Edge[i].fi, Edge[i].se);
int v = Edge[i].se;
if((in(v, R) && in(v, Exit)) || (!in(v, R) && !in(v, Exit))){
cout << "escaped\n";
}
else{
del[i] = true;
ll val = BFS(R);
if(val == inf){
cout << "oo\n";
}
else cout << val <<"\n";
del[i] = false;
}
}
}
int32_t main()
{
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
#define name "task"
if(fopen(name".INP", "r")){
freopen(name".INP", "r", stdin);
freopen(name".ANS", "w", stdout);
}
solve();
return 0;
}
