#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define ull unsigned long long
#define ii pair <int, int>
#define ill pair <ll, ll>
#define ild pair <ld, ld>
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define file "test"
using namespace std;
const int N = 2e5 + 2;
const int M = 20;
const ll MOD = 1e9 + 7;
const ll INF = 1e18;
const ll base = 311;
const int BLOCK_SIZE = 400;
int n, s, q, e;
ii a[N];
ll w[N], f[N], d[N];
ll h[N], up[N][20], fu[N][20];
vector <int> g[N];
void dfs(int u, int p) {
for (int i: g[u]) {
int v = a[i].fi ^ a[i].se ^ u;
if (v == p) continue;
h[v] = h[u] + 1;
d[v] = d[u] + w[i];
up[v][0] = u;
for (int j = 1; j < M; j ++)
up[v][j] = up[up[v][j - 1]][j - 1];
dfs(v, u);
f[u] = min(f[u], f[v] + w[i]);
}
}
void dfs2(int u, int p) {
for (int i: g[u]) {
int v = a[i].fi ^ a[i].se ^ u;
if (v == p) continue;
fu[v][0] = f[u] - d[u];
for (int j = 1; j < M; j ++)
fu[v][j] = min(fu[v][j - 1], fu[up[v][j - 1]][j - 1]);
dfs2(v, u);
}
}
int jump(int u, int k) {
for (int j = 0; j < M; j ++)
if (k >> j & 1) u = up[u][j];
return u;
}
bool is_anc(int u, int p) {
return jump(u, h[u] - h[p]) == p;
}
ll get(int u, int k) {
ll res = INF;
for (int j = 0; j < M; j ++)
res = min(res, fu[u][j]), u = up[u][j];
return res;
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> n >> s >> q >> e;
for (int i = 1; i < n; i ++) {
cin >> a[i].fi >> a[i].se >> w[i];
f[i] = INF;
g[a[i].fi].push_back(i);
g[a[i].se].push_back(i);
}
f[n] = INF;
for (int i = 0, u; i < s; i ++)
cin >> u, f[u] = 0;
for (int i = 0; i < 20; i ++)
for (int j = 1; j <= n; j ++) fu[j][i] = INF;
dfs(e, 0);
dfs2(e, 0);
for (int i = 1; i < n; i ++) {
auto [u, v] = a[i];
if (h[u] < h[v]) swap(a[i].fi, a[i].se);
}
while (q --) {
int i, r; cin >> i >> r;
int u = a[i].fi;
if (!is_anc(r, u))
cout << "escaped\n";
else if (f[u] == INF)
cout << "oo\n";
else cout << min(d[r] + get(r, h[r] - h[u]), f[r]) << '\n';
}
}
/*
/\_/\ zzZ
(= -_-)
/ >u >u
*/
