#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define endl '\n'
const int N = 1e5 + 5;
long long mod = 998244353;
const int lim = 4e5 + 5;
const int lg = 22;
const int base = 311;
const long double eps = 1e-6;
struct viet{
ll u, v, w;
};
vector<viet> E;
ll dp[N][lg + 1], par[N][lg + 1], dep[N], a[N], dep2[N];
vector<pair<ll, ll>> node[N];
void dfs2(ll u, ll p){
for (int i = 1; i <= lg; i++){
dp[u][i] = min(dp[u][i - 1], dp[par[u][i - 1]][i - 1]);
}
for (auto j : node[u]){
if (j.first == p) continue;
dfs2(j.first, u);
}
}
void dfs(ll u, ll p){
for (int i = 1; i <= lg; i++){
par[u][i] = par[par[u][i - 1]][i - 1];
}
dp[u][0] = 1e18;
for (auto j : node[u]){
if (j.first == p) continue;
par[j.first][0] = u;
dep[j.first] = dep[u] + j.second;
dep2[j.first] = dep2[u] + 1;
dfs(j.first, u);
dp[u][0] = min(dp[u][0], dp[j.first][0] + j.second * 2);
}
if (a[u]) dp[u][0] = -dep[u];
}
ll check(ll u, ll v){
ll dist = dep2[v] - dep2[u];
if (dist < 0) return 0;
for (int i = 0; i <= lg; i++){
if (dist & (1 << i)){
v = par[v][i];
}
}
if (v == u) return 1;
else return 0;
}
ll get(ll u, ll v){
ll dist = dep2[u] - dep2[v];
ll res = 1e18;
ll dd = dep[u];
for (int i = 0; i <= lg; i++){
if (dist & (1 << i)){
res = min(res, dd + dp[u][i]);
u = par[u][i];
}
}
res = min(res, dd + dp[u][0]);
return res;
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
if (fopen("tests.inp", "r")){
freopen("test.inp", "r", stdin);
freopen("test.out", "w", stdout);
}
ll n, s, q, e;
cin >> n >> s >> q >> e;
for (int i = 1; i < n; i++){
ll u, v, w;
cin >> u >> v >> w;
E.push_back({u, v, w});
node[u].push_back({v, w});
node[v].push_back({u, w});
}
for (int i = 1; i <= s; i++){
ll x;
cin >> x;
a[x] = 1;
}
for (int i = 1; i <= n; i++){
for (int j = 1; j <= lg; j++){
dp[i][j] = 1e18;
}
}
dfs(e, e);
dfs2(e, e);
while (q--){
ll u, v;
cin >> v >> u;
ll n1 = E[v - 1].u;
ll n2 = E[v - 1].v;
if (dep[n1] < dep[n2]) swap(n1, n2);
if (!check(n1, u)) cout << "escaped" << endl;
else {
ll x = get(u, n1);
if (x > 1e17) cout << "oo" << endl;
else cout << x << endl;
}
}
}
/*
Ans:
Out:
*/
