/* In the name of God, aka Allah */
// let this be mytemp.cpp
#include<bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define endl '\n'
#define mk make_pair
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const ll inf = 1e18;
const int N = 1e5 + 50, LG = 20;
ll n, s, q, e, par[LG][N], sp[LG][N], dp[N], h[N], dis[N];
pll E[N];
vector<pll> adj[N];
void dfs(int u, int p) {
par[0][u] = p;
for (pll x:adj[u]) {
int v = x.F, w = x.S;
if (v == p) continue;
dis[v] = dis[u]+w;
h[v] = h[u] + 1;
dfs(v, u);
dp[u] = min(dp[u], dp[v]+w);
}
sp[0][u] = dp[u]-dis[u];
}
pll Par(int u, int x) {
ll out = inf;
for (int k = LG-1; k >= 0; k--) {
if (x>>k&1) {
out = min(out, sp[k][u]);
u = par[k][u];
}
}
out = min(out, sp[0][u]);
return {u, out};
}
void solve() {
cin >> n >> s >> q >> e;
for (int i = 1; i <= n-1; i++) {
int u, v, w;
cin >> u >> v >> w;
adj[u].push_back({v, w});
adj[v].push_back({u, w});
E[i] = {u, v};
}
for (int u = 1; u <= n; u++) {
dp[u] = inf;
}
for (int i = 1; i <= s; i++) {
int u;
cin >> u;
dp[u] = 0;
}
dfs(e, 0);
for (int i = 1; i <= n-1; i++) {
if (h[E[i].F] < h[E[i].S]) swap(E[i].F, E[i].S);
}
for (int k = 1; k < LG; k++) {
for (int u = 1; u <= n; u++) {
par[k][u] = par[k-1][par[k-1][u]];
sp[k][u] = min(sp[k-1][u],sp[k-1][par[k-1][u]]);
}
}
while (q--) {
int u, id;
cin >> id >> u;
pll out = Par(u, h[u]-h[E[id].F]);
if (out.F != E[id].F) {
cout << "escaped" << endl;
}
else {
ll ans = out.S + dis[u];
if (ans >= inf) cout << "oo" << endl;
else cout << ans << endl;
}
}
}
int main() {
ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
solve();
return 0;
}
