#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <bits/stdc++.h>
#define fi first
#define se second
#define pb push_back
#define sz(a) (int)a.size()
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define ff(i,a,b) for(int i=a;i<=b;i++)
#define fb(i,b,a) for(int i=b;i>=a;i--)
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef pair<int,ll> pii;
const int maxn = 100005;
const ll inf = 1e18 + 5;
template<typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
// os.order_of_key(k) the number of elements in the os less than k
// *os.find_by_order(k) print the k-th smallest number in os(0-based)
int n, q, k, R;
pii niz[maxn];
vector<pii> g[maxn];
bool mark[maxn];
int d[maxn];
ll dist[maxn];
ll kol[maxn];
void dfs1(int v, int p){
if(mark[v])kol[v] = 0;
else kol[v] = inf;
for(auto c : g[v]){
int u = c.fi;
ll w = c.se;
if(u != p){
d[u] = d[v] + 1;
dist[u] = dist[v] + w;
dfs1(u, v);
kol[v] = min(kol[v], w + kol[u]);
}
}
}
ll dud[maxn];
void upd(int x, ll val){
while(x <= maxn){
dud[x] += val;
x += x&(-x);
}
}
ll query(int x){
ll sum = 0;
while(x > 0){
sum += dud[x];
x -= x&(-x);
}
return sum;
}
int timer = 0;
int in[maxn];
int out[maxn];
int deda[maxn][20];
ll mn[maxn][20];
void dfs2(int v, int p, ll pw){
in[v] = ++timer;
if(mark[v])upd(in[v], 1);
deda[v][0] = p;
mn[v][0] = pw;
ff(i,1,19){
deda[v][i] = deda[deda[v][i - 1]][i - 1];
mn[v][i] = min(mn[v][i - 1], mn[deda[v][i - 1]][i - 1]);
}
for(auto c : g[v]){
int u = c.fi;
ll w = c.se;
if(u != p){
dfs2(u, v, (kol[v] == inf ? inf : kol[v] - dist[v]));
}
}
out[v] = timer;
}
bool predak(int x, int y){
return (in[x] <= in[y] && out[x] >= out[y]);
}
ll calc(int x, int y){
ll najm = inf;
fb(i,19,0){
if(y & (1 << i)){
najm = min(najm, mn[x][i]);
x = deda[x][i];
}
}
return najm;
}
int main()
{
ios::sync_with_stdio(false);
cout.tie(nullptr);
cin.tie(nullptr);
cin >> n >> k >> q >> R;
ff(i,1,n - 1){
int u, v;
ll w;
cin >> u >> v >> w;
g[u].pb({v, w});
g[v].pb({u, w});
niz[i] = {u, v};
}
ff(i,1,k){
int x;
cin >> x;
mark[x] = 1;
}
dfs1(R, -1);
dfs2(R, -1, 0);
while(q--){
int id, s;
cin >> id >> s;
int u = niz[id].fi;
int v = niz[id].se;
if(d[u] < d[v])swap(u, v);
// 1 - slucaj, ako je izvan subtree-a u
if(!predak(u, s)){
cout << "escaped" << endl;
continue;
}
// nema valley u subtree od u
if(query(out[u]) - query(in[u] - 1) == 0){
cout << "oo" << endl;
continue;
}
ll dole = kol[s];
ll gore = calc(s, d[s]) + dist[s];
cout << min(dole, gore) << endl;
}
return 0;
}
/**
5 2 3 1
1 2 3
1 3 2
3 4 1
3 5 2
2
4
// probati bojenje sahovski ili slicno
**/
