#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
#define Mp make_pair
#define sep ' '
#define endl '\n'
#define F first
#define S second
#define pb push_back
#define all(x) (x).begin(),(x).end()
#define kill(res) cout << res << '\n';
#define set_dec(x) cout << fixed << setprecision(x);
#define fast_io ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define file_io freopen("input.txt", "r", stdin) ; freopen("output.txt", "w", stdout);
const ll L = 20;
const ll N = 1e5 + 7;
const ll inf = 1e18 + 7;
ll n, S, q, E, h[N], st[N], ft[N], timer, par[N][L], naz[N][L], sub[N][3], dist[N][L];
pll edge[N];
bool mark[N], red[N];
vector<pll> adj[N];
void dfs(int v){
st[v] = ++timer;
ll mn = inf, mn2 = inf, idx;
mark[v] = true;
for(auto u: adj[v]){
if(!mark[u.F]){
h[u.F] = h[v] + 1;
dfs(u.F);
if(sub[u.F][0] + u.S < mn){
mn = sub[u.F][0] + u.S;
idx = u.F;
}
else if(sub[u.F][0] + u.S < mn2){
mn2 = sub[u.F][0] + u.S;
}
}
}
if(!red[v]){
sub[v][0] = mn;
sub[v][1] = idx;
sub[v][2] = mn2;
}
ft[v] = ++timer;
}
void build(int v, ll w = inf, int parent = 0){
if(v != sub[parent][1]) naz[v][0] = sub[parent][0] + w;
else naz[v][0] = sub[parent][2] + w;
dist[v][0] = w;
par[v][0] = parent;
for(int i = 1; i < L; i++){
//if(!par[v][i-1]) break;
par[v][i] = par[par[v][i-1]][i-1];
dist[v][i] = dist[v][i-1] + dist[par[v][i-1]][i-1];
naz[v][i] = min(naz[v][i-1], naz[par[v][i-1]][i-1] + dist[v][i-1]);
}
mark[v] = true;
for(auto u: adj[v]){
if(!mark[u.F]){
build(u.F, u.S, v);
}
}
}
int main(){
fast_io;
cin >> n >> S >> q >> E;
int u, v, w;
for(int i = 1; i < n; i++){
cin >> u >> v >> w;
adj[u].pb(Mp(v, w));
adj[v].pb(Mp(u, w));
edge[i] = Mp(u, v);
}
for(int i = 1; i <= S; i++){
cin >> v;
red[v] = true;
}
for(int i = 0; i < N; i++){
fill(naz[i], naz[i] + L, inf);
fill(dist[i], dist[i] + L, inf);
}
sub[0][0] = sub[0][2] = inf;
dfs(E);
fill(mark, mark + N, 0); build(E);
/*for(int i = 1; i <= n; i++){
for(int j = 0; j < 5; j++){
cout << i << sep << j << sep << naz[i][j] << sep << dist[i][j] << sep << par[i][j] << endl;
}
}*/
int ii, r;
while(q--){
cin >> ii >> r;
int u = edge[ii].F;
int v = edge[ii].S;
if(h[v] < h[u]) swap(u, v);
if(st[E] <= st[u] && ft[u] <= ft[E] && st[v] <= st[r] && ft[r] <= ft[v]){
ll res = sub[r][0], fas = 0;
int c = r;
for(int i = L-1; i >= 0; i--){
if(h[par[c][i]] < h[v]) continue;
res = min(res, naz[c][i] + fas);
fas += dist[c][i]; c = par[c][i];
}
if(res >= inf){
cout << "oo" << endl; continue;
}
cout << res << endl;
}
else{
cout << "escaped" << endl;
}
}
}
