/* Author : Mychecksdead */
#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define PI 3.1415926535
#define pb push_back
#define setp() cout << setprecision(15)
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " is " << x << '\n';
const int N = 1e6+100, M = 1e5+10, F = 2147483646, K = 20;
int n, s, q, E, tin[N], tout[N], timer = 0, up[N][K], dep[N];
vector<bool> c(N);
vector<array<int, 2>> g[N], edges;
ll dist[N], dp[N][K], d[N];
void pre(int v, int p){
tin[v] = timer++;
up[v][0] = p;
dist[v] = 1e18;
dep[v] = dep[p] + 1;
for(auto k: g[v]){
if(k[0] != p){
d[k[0]] = d[v] + k[1];
pre(k[0], v);
dist[v] = min(dist[v], dist[k[0]] + k[1]);
}
}
if(c[v]) dist[v] = 0;
tout[v] = timer++;
}
bool is_ancestor(int u, int v){
return tin[u] <= tin[v] && tout[v] <= tout[u];
}
void solve(){
cin >> n >> s >> q >> E;
for(int i = 0; i < n - 1; ++i){
int u, v, e; cin >> u >> v >> e;
g[u].pb({v, e});
g[v].pb({u, e});
edges.pb({u, v});
}
for(int i = 1; i <= s; ++i){
int x; cin >> x;
c[x] = 1;
}
d[E] = dep[E] = 0;
pre(E, E);
for(int i = 1; i <= n; ++i) dp[i][0] = min(dist[i], dist[up[i][0]] + (d[i] - d[up[i][0]]));
for(int j = 1; j < K; ++j){
for(int i = 1; i <= n; ++i){
up[i][j] = up[up[i][j - 1]][j - 1];
dp[i][j] = min(dp[i][j - 1], dp[up[i][j - 1]][j - 1] + (d[i] - d[up[i][j - 1]]));
}
}
for(;q--;){
int i, v; cin >> i >> v;
int a = edges[i - 1][0], b = edges[i - 1][1];
if(is_ancestor(a, b)) swap(a, b);
if(!is_ancestor(a, v)){
cout << "escaped";
}else{
ll best = dist[v], cur = 0;
for(int i = K - 1; i >= 0; --i){
if((1<<i)&(dep[v] - dep[a])){
best = min(best, dp[v][i] + cur);
cur += d[v] - d[up[v][i]];
v = up[v][i];
}
}
if(best == 1e18) cout << "oo";
else cout << best;
}
cout << '\n';
}
}
int main(){
cin.tie(0); ios::sync_with_stdio(0);
int T = 1, aa;
// cin >> T;aa=T;
while(T--){
// cout << "Case #" << aa-T << ": ";
solve();
cout << '\n';
}
return 0;
}
