#include "bits/extc++.h"
using namespace std;
template <typename T>
void dbgh(const T& t) {
cerr << t << endl;
}
template <typename T, typename... U>
void dbgh(const T& t, const U&... u) {
cerr << t << " | ";
dbgh(u...);
}
#ifdef DEBUG
#define dbg(...) \
cerr << "L" << __LINE__ << " [" << #__VA_ARGS__ << "]" \
<< ": "; \
dbgh(__VA_ARGS__)
#else
#define cerr \
if (false) \
cerr
#define dbg(...)
#endif
#define endl "\n"
#define long int64_t
#define sz(x) int((x).size())
const int maxn = 1e5 + 5, logn = 20;
bool village[maxn];
int t, tin[maxn], tout[maxn], blift[logn][maxn];
long st[maxn], dist[logn][maxn], bliftv[logn][maxn];
vector<pair<int, long>> graph[maxn];
long dfs(int u, int par = -1) {
tin[u] = t++;
blift[0][u] = par;
long ans = 1e18;
if (village[u]) {
ans = 0;
}
for (auto& [v, w] : graph[u]) {
if (v != par) {
dist[0][v] = w;
ans = min(ans, w + dfs(v, u));
}
}
tout[u] = t++;
return bliftv[0][u] = st[u] = ans;
}
bool anc(int u, int v) {
return tin[u] <= tin[v] && tout[v] <= tout[u];
}
void solve() {
int n, s, q, e;
cin >> n >> s >> q >> e;
e--;
int edges[n - 1][2];
for (auto& [u, v] : edges) {
int w;
cin >> u >> v >> w;
u--;
v--;
graph[u].emplace_back(v, w);
graph[v].emplace_back(u, w);
}
for (int i = 0; i < s; i++) {
int u;
cin >> u;
u--;
village[u] = true;
}
dfs(e);
for (int i = 1; i < logn; i++) {
for (int j = 0; j < n; j++) {
int v = blift[i - 1][j];
if (v != -1) {
blift[i][j] = blift[i - 1][v];
dist[i][j] = dist[i - 1][j] + dist[i - 1][v];
bliftv[i][j] = min(bliftv[i - 1][j], dist[i - 1][j] + bliftv[i - 1][v]);
} else {
blift[i][j] = -1;
}
}
}
dbg(bliftv[0][6]);
while (q--) {
int road, x;
cin >> road >> x;
road--;
x--;
auto [u, v] = edges[road];
if (anc(u, x) && anc(v, x)) {
if (anc(v, u)) {
swap(u, v);
}
if (st[v] >= long(1e18)) {
cout << "oo" << endl;
continue;
}
long ans = 1e18, cd = 0;
for (int i = logn - 1; i >= 0; i--) {
int y = blift[i][x];
if (y != -1 && (anc(v, y) || v == y)) {
ans = min(ans, cd + bliftv[i][x]);
cd += dist[i][x];
x = y;
}
}
ans = min(ans, cd + st[v]);
cout << ans << endl;
} else {
cout << "escaped" << endl;
}
}
}
int main() {
cin.tie(nullptr);
ios_base::sync_with_stdio(false);
cin.exceptions(ios::failbit);
solve();
}
