#include<bits/stdc++.h>
#define pl(a) " [" << #a << ": " << (a) << "] "
#define pts(a) " [" << #a << ": { first: " << (a.first) << ", second: " << (a.second) << "}] "
#define all(vi) vi.begin(), vi.end()
#define endl "\n"
#define int long long int
using namespace std;
pair<int, int> n4[4] { {1, 0}, {-1, 0}, {0, 1}, {0, -1} };
pair<int, int> n8[8] { {1, 0}, {-1, 0}, {0, 1}, {0, -1}, {1, 1}, {-1, -1}, {-1, 1}, {1, -1} };
int h(int x1, int y1, int x2, int y2) { return abs(x2 - x1) + abs(y2 - y1); }
template<typename A> ostream& operator<<(ostream &cout, vector<A> const &v);
template<typename A, typename B> ostream& operator<<(ostream &cout, pair<A, B> const &p) { return cout << "[" << p.first << ", " << p.second << "]"; }
template<typename A> ostream& operator<<(ostream &cout, vector<A> const &v) { cout << "["; for(int i = 0; i < v.size(); i++) {if (i) cout << ", "; cout << v[i];} return cout << "]";}
template<typename A, typename B> istream& operator>>(istream& cin, pair<A, B> &p) { cin >> p.first; return cin >> p.second; }
int pow(int x, int y) {
if (y == 0) return 1;
if (y % 2 == 0) {
int a = pow(x, y / 2);
return a * a;
} else {
int a = pow(x, y / 2);
a = a * a;
return a * x;
}
assert(false);
return 0;
}
void set_in(string s) {
if (s.length() > 0) {
freopen ((s+".in").c_str(), "r", stdin);
freopen ((s+".out").c_str(), "w", stdout);
}
}
vector<vector<pair<int, int>>> adj;
vector<pair<pair<int, int>, int>> edges;
int n, s, q, e, r;
vector<bool> shop;
vector<int> dist, dp, p, depth;
void dfs(int u, int par, int d, int dep) {
dist[u] = d;
p[u] = par;
depth[u] = dep;
for (auto [v, w] : adj[u]) {
if (v == par) continue;
dfs(v, u, d + w, dep + 1);
}
dp[u] = 1e18;
if (shop[u]) dp[u] = dist[u];
for (auto [v, w] : adj[u]) {
if (v == par) continue;
dp[u] = min(dp[u], dp[v]);
}
}
void solve() {
cin >> n >> s >> q >> e;
shop.resize(n);
dist.resize(n);
dp.resize(n);
p.resize(n);
depth.resize(n);
adj.resize(n);
for (int i = 0; i < n - 1; i++) {
int a, b, c; cin >> a >> b >> c;
a--, b--;
edges.emplace_back(make_pair(a, b), c);
adj[a].emplace_back(b, c);
adj[b].emplace_back(a, c);
}
for (int i = 0; i < s; i++) {
int a; cin >> a;
shop[a - 1] = 1;
}
e--;
dfs(e, e, 0, 0);
for (int i = 0; i < n; i++) {
dp[i] -= 2 * dist[i];
}
// build the sparse table
vector<vector<int>> jmp(n, vector<int>(32, -1));
vector<vector<int>> jmpdp(n, vector<int>(32, 1e18));
for (int i = 0; i < n; i++) {
jmp[i][0] = p[i];
jmpdp[i][0] = min(dp[i], dp[p[i]]);
}
for (int i = 1; i < 32; i++) {
for (int j = 0; j < n; j++) {
jmp[j][i] = jmp[jmp[j][i - 1]][i - 1];
jmpdp[j][i] = min({
jmpdp[j][i - 1],
jmpdp[jmp[j][i - 1]][i - 1]
});
}
}
auto best = [&](int u, int k) {
int res = dp[u];
int pow = 31;
while (k > 0) {
if (k - (1ll << pow) >= 0) {
k -= (1ll << pow);
res = min(res, jmpdp[u][pow]);
u = jmp[u][pow];
}
pow--;
}
return res;
};
auto check = [&](int u, int v) { // u is above v?
int pow = 31;
int k = depth[v] - depth[u];
while (k > 0) {
if (k - (1ll << pow) >= 0) {
k -= (1ll << pow);
v = jmp[v][pow];
}
pow--;
}
return u == v;
};
while (q--) {
int a, b; cin >> a >> b;
a--, b--;
auto ee = edges[a].first;
if (check(ee.first, b) && check(ee.second, b)) {
int one = ee.first;
if (depth[ee.second] > depth[ee.first]) one = ee.second;
int res = best(b, depth[b] - depth[one]);
if (res >= 1e16) {
cout << "oo" << endl;
} else {
cout << res + dist[b] << endl;
}
} else {
cout << "escaped" << endl;
}
}
}
void precomp() {
}
int32_t main() {
#ifndef DEBUG
set_in("");
#endif
#ifdef DEBUG
auto clock_start = chrono::high_resolution_clock::now();
cout << endl;
#endif
ios::sync_with_stdio(false);
cin.tie(nullptr);
cout << setprecision(16) << fixed;
int T = 1;
// cin >> T;
precomp();
for (int t = 1; t <= T; t++) {
// cout << "Case #" << t << ": ";
solve();
}
// Clock
#ifdef DEBUG
auto clock_end = chrono::high_resolution_clock::now();
cout << endl;
chrono::duration<double> elapsed = clock_end - clock_start;
cout << "Execution time: " << elapsed.count() << "s" << endl;
#endif
return 0;
}
