#include <bits/stdc++.h>
#define name ""
#define test "test"
#define int ll
#define ll long long
#define ld long double
#define fi first
#define se second
#define pll pair < ll, ll >
#define pii pair < int, int >
#define fast ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define sz(x) ((int)(x).size())
#define pb push_back
#define mp make_pair
using namespace std;
const ld EPS = 1e-9;
const int INF = 1e9 + 7;
const ll LINF = 1E18;
const int NMAX = 2e5;
const ll MOD = 1e9 + 7;
const ll BASE = 2309;
int n, s, q, root, in[100003], out[100003], timer = 0, h[100003], par[100003][20];
bool shop[100003];
pii edges[100003];
ll dis[100003], f[100003], g[100003][20];
vector < pll > adj[100003];
void dfs(int u, int e, ll len) {
in[u] = out[u] = ++ timer;
dis[u] = len;
f[u] = (shop[u] ? 0 : LINF);
h[u] = h[e] + 1;
for (auto v : adj[u]) {
if (v.fi == e) continue;
par[v.fi][0] = u;
for (int i = 1; i <= 19; i++)
par[v.fi][i] = par[par[v.fi][i - 1]][i - 1];
dfs(v.fi, u, len + v.se);
f[u] = min(f[u], f[v.fi] + v.se);
}
out[u] = timer;
}
void dfs2(int u, int e) {
for (auto v : adj[u]) {
if (v.fi == e) continue;
g[v.fi][0] = f[u] - dis[u];
for (int i = 1; i <= 19; i++) {
g[v.fi][i] = min(g[v.fi][i - 1], g[par[v.fi][i - 1]][i - 1]);
}
dfs2(v.fi, u);
}
}
signed main() {
fast;
if(fopen(name".inp", "r")) {
freopen(name".inp", "r", stdin);
freopen(name".out", "w", stdout);
}
//int t; cin >> t; while (t --) sol();
cin >> n >> s >> q >> root;
for (int i = 1; i < n; i++) {
ll u, v, c; cin >> u >> v >> c;
adj[u].push_back({v, c}); adj[v].push_back({u, c});
edges[i] = {u, v};
}
for (int i = 1; i <= s; i++) {
int x; cin >> x;
shop[x] = 1;
}
dfs(root, 0, 0);
dfs2(root, 0);
while (q--) {
int id, node; cin >> id >> node;
int u = edges[id].fi, v = edges[id].se;
if (par[u][0] == v) swap(u, v);
if (!(in[v] <= in[node] && in[node] <= out[v])) {
cout << "escaped" << '\n';
continue;
}
if (f[v] >= LINF) {
cout << "oo" << '\n';
continue;
}
ll res = f[node], d = h[node] - h[v], val = dis[node];
for (int i = 19; i >= 0; i--) {
if (d >> i & 1) {
res = min(res, val + g[node][i]);
node= par[node][i];
}
}
if (res > 1ll * n * INF) cout << "oo" << '\n';
else cout << res << '\n';
}
}
