#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int tim;
vector<bool> vis;
vector<int> d, tin, tout, sz, pr;
vector<ll> v, dis1;
vector<vector<pair<int, int>>> E;
void dfs(int x, int p = -1) {
tin[x] = tim++;
if (~p) d[x] = d[p] + 1;
for (auto [i, w] : E[x]) {
if (i != p) {
dfs(i, x);
v[x] = min(v[x], v[i] + w);
}
}
tout[x] = tim++;
}
int dfs_sz(int x, int p = -1) {
sz[x] = 1;
for (auto [i, w] : E[x])
if (!vis[i] && i != p) sz[x] += dfs_sz(i, x);
return sz[x];
}
int fnd(int x, int n, int p = -1) {
for (auto [i, w] : E[x])
if (!vis[i] && i != p && sz[i] > (n >> 1)) return fnd(i, n, x);
return x;
}
void dfs_dis(int x, int c, int cp, int p = -1, ll ds = 0) {
for (auto [i, w] : E[x]) {
if (vis[i]) {
if (i == cp) dis1[c] = ds + w;
}
else if (i != p) dfs_dis(i, c, cp, x, ds + w);
}
}
void f(int x, int p = -1) {
int n = dfs_sz(x), c = fnd(x, n);
pr[c] = p;
if (~p) dfs_dis(c, c, p);
vis[c] = true;
for (auto [i, w] : E[c])
if (!vis[i]) f(i, c);
}
int main() {
ios::sync_with_stdio(false); cin.tie(nullptr);
int n, s, q, e;
cin >> n >> s >> q >> e; e--;
E.assign(n, {});
vector<int> eu(n - 1), ev(n - 1), ew(n - 1);
for (int i = 0; i < n - 1; i++) {
cin >> eu[i] >> ev[i] >> ew[i]; eu[i]--; ev[i]--;
E[eu[i]].push_back({ev[i], ew[i]});
E[ev[i]].push_back({eu[i], ew[i]});
}
v.assign(n, (ll)1e18);
while (s--) {
int x;
cin >> x; x--;
v[x] = 0;
}
d.assign(n, 0);
sz.assign(n, 0);
pr.assign(n, 0);
tin.assign(n, 0);
tout.assign(n, 0);
dis1.assign(n, 0);
vis.assign(n, false);
dfs(e);
for (int i = 0; i < n - 1; i++)
if (d[eu[i]] > d[ev[i]]) swap(eu[i], ev[i]);
f(0);
while (q--) {
int ind, x;
cin >> ind >> x; ind--; x--;
if (!(tin[ev[ind]] <= tin[x] && tout[x] <= tout[ev[ind]])) {
cout << "escaped\n"; continue;
}
ll mn = (ll)1e18, sm = 0;
while (d[x] > d[eu[ind]]) {
mn = min(mn, v[x] + sm);
sm += dis1[x];
if (!~pr[x]) break;
x = pr[x];
}
int y = ev[ind];
if (d[x] > d[y]) {
vector<int> u;
while (x != y) {
u.push_back(y);
y = pr[y];
}
while (!u.empty()) {
sm += dis1[u.back()];
mn = min(mn, v[u.back()] + sm);
u.pop_back();
}
}
if (mn == (ll)1e18) cout << "oo\n";
else cout << mn << '\n';
}
}
