#include<bits/stdc++.h>
using namespace std;
#define i64 long long
#define mp make_pair
#define pb push_back
#define all(x) (x).begin(), (x).end()
const i64 INF = 1e18;
const int MAXN = 100015;
int villages, shops, Q, exitP, h[MAXN], up[MAXN][22];
int counter = 0, tin[MAXN], tout[MAXN];
i64 d[MAXN], mind[MAXN], upd[MAXN][22];
bool isShop[MAXN];
pair<int, int> Edges[MAXN];
vector<pair<int, int>> G[MAXN];
void dfs(int u) {
tin[u] = tout[u] = ++counter;
if (isShop[u]) mind[u] = d[u];
else mind[u] = INF;
for (auto [v, w] : G[u]) {
if (v != up[u][0]) {
up[v][0] = u;
d[v] = d[u] + w;
h[v] = h[u] + 1;
for (int j = 1; j <= 20; j ++) {
up[v][j] = up[up[v][j - 1]][j - 1];
}
dfs(v);
mind[u] = min(mind[u], mind[v]);
}
}
tout[u] = counter;
}
void dfs1(int u) {
for (auto [v, w] : G[u]) {
if (v != up[u][0]) {
upd[v][0] = mind[u];
for (int j = 1; j <= 20; j ++) {
upd[v][j] = min(upd[v][j - 1], upd[up[v][j - 1]][j - 1]);
}
dfs1(v);
}
}
}
void Solve (void) {
cin >> villages >> shops >> Q >> exitP;
for (int i = 1; i <= villages; i ++) isShop[i] = false;
for (int i = 1; i < villages; i ++) {
int u, v, w; cin >> u >> v >> w;
G[u].pb(mp(v, w));
G[v].pb(mp(u, w));
Edges[i] = mp(u, v);
}
for (int i = 1; i <= shops; i ++) {
int x; cin >> x;
isShop[x] = true;
}
dfs(exitP);
for (int i = 1; i <= villages; i ++) {
if (mind[i] != INF) mind[i] = mind[i] - 2 * d[i];
}
dfs1(exitP);
while (Q --) {
int RoadID, st; cin >> RoadID >> st;
auto [u, v] = Edges[RoadID];
if (h[v] < h[u]) swap(u, v);
if (tin[v] <= tin[st] && tout[st] <= tout[v]) {
// Lie in subtree
int gap = h[st] - h[v];
i64 mn = mind[st], add = d[st];
for (int j = 20; j >= 0; j --) {
if (gap >> j & 1) {
mn = min(mn, upd[st][j]);
st = up[st][j];
}
}
if (mn >= INF) cout << "oo" << "\n";
else cout << mn + add << "\n";
} else {
cout << "escaped" << "\n";
}
}
}
signed main() {
ios_base::sync_with_stdio(false); cin.tie(0);
// Prepare();
int Tests = 1; // cin >> Tests;
while (Tests --) {
Solve();
}
}
