/*
* prep: 4.3
*/
#include<bits/stdc++.h>
using namespace std;
#define fr first
#define sc second
#define pb push_back
#define mp make_pair
#define ll long long
using i64 = long long;
#ifdef LOCAL
#define eprintf(...) {fprintf(stderr, __VA_ARGS__);fflush(stderr);}
#else
#define eprintf(...) 42
#endif
int N = (int)1e5 + 1;
int n,s,q,e;
int t = 0;
ll inf = (ll)1e15;
vector<i64> in(N), out(N), shop(N), x(N, inf), dp(N), d(N);
vector<pair<int, int>> id(N);
vector<vector<pair<int, int>>> adj(N);
vector<vector<i64>> up(N, vector<i64>(20)), dp2(N, vector<i64>(20));
void DepthFirstSearch(int u, int p){
up[u][0] = p;
x[u]=inf;
in[u]=++t;
if (shop[u]) {
x[u] = d[u];
}
for (auto [v, w] : adj[u]) {
if (v != p) {
d[v] = d[u] + w;
DepthFirstSearch(v, u);
x[u] = min(x[u], x[v]);
}
}
out[u]=t - 1;
dp[u] = (x[u] == inf ? inf : x[u] - 2 * d[u]);
dp2[u][0] = dp[u];
}
bool inside(int u, int from){
return (in[u]<=in[from] && out[u] >= out[from]);
}
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
cin >> n >> s >> q >> e;
for (int i=0 ; i < n - 1; i++){
int a,b,w;
cin >> a >> b >> w;
adj[a].pb(mp(b,w));
adj[b].pb(mp(a,w));
id[i+1] = mp(a,b);
}
for(int i = 0; i < s; ++i){
int j;cin >> j;
shop[j]=1;
}
DepthFirstSearch(e,e);
for (int i = 1; i<20; i++){
for (int j = 1; j<=n; j++){
up[j][i] = up[up[j][i-1]][i-1];
dp2[j][i] = min(dp2[j][i-1], dp2[up[j][i-1]][i-1]);
}
}
while(q--){
int i, r;
cin >> i >> r;
auto [u, v] = id[i];
if (inside(u, v)) {
swap(u, v);
}
if (!inside(u, r)) {
cout << "escaped\n";
} else {
i64 best = dp[u], dd = d[r];
for (int b = 19; b >= 0; b--) {
if (inside(u, up[r][b])) {
best = min(best, dp2[r][b]);
r = up[r][b];
}
}
if (best == inf) {
cout << "oo\n";
} else {
cout << dd + best << '\n';
}
}
}
return 0;
}
