#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define int ll
using P = pair<int, int>;
#define all(x) x.begin(), x.end()
#define rep(i, l, n) for (int i = l; i < (n); ++i)
#define sz(x) (int)x.size()
const char nl = '\n';
const int mod = 998244353;
const int NMAX = 1e5+10;
const int inf = 1e5*1e9+10;
struct edge{
int v, w, id;
};
P E[NMAX];
vector<edge> g[NMAX];
int tin[NMAX], tout[NMAX];
int d[NMAX], s[NMAX], opt[NMAX];
int d2[NMAX];
int t = 0;
void dfs(int nd, int p = -1, int v = -1) {
tin[nd] = t++, opt[nd] = v;
for (auto ch: g[nd]) {
if (ch.v == p)continue;
E[ch.id] = {nd, ch.v};
s[ch.v] = s[nd]+ch.w;
dfs(ch.v, nd, (d[nd] == 0?nd:v));
d[nd] = min(d[nd], d[ch.v]+ch.w);
}
d2[nd] = d[nd]-s[nd];
for (auto ch: g[nd])
if (ch.v != p)
d2[nd] = min(d2[nd], d2[ch.v]);
tout[nd] = t-1;
}
bool f(int l, int r, int x) {
if (l <= x && x <= r)return 1;
return 0;
}
void solve() {
int n, ss, q, e;
cin >> n >> ss >> q >> e;
rep(i, 1, n+1)d[i] = d2[i] = inf;
rep(i, 1, n) {
int u, v, w; cin >> u >> v >> w;
g[u].push_back({v, w, i});
g[v].push_back({u, w, i});
}
rep(i, 0, ss) {
int c; cin >> c;
d[c] = 0;
}
dfs(e);
while (q--) {
int I, R; cin >> I >> R;
int v = E[I].second;
int a = f(tin[v], tout[v], tin[R]);
if (!a)cout << "escaped\n";
else {
int uc = inf;
if (opt[R] != -1 && f(tin[v], tout[v], tin[opt[R]]))uc = s[R]-s[opt[R]];
int res = min(min(d[R], s[R]+d[v]), min(d[v]+s[R]-s[v], uc));
if (res == inf)cout << "oo" << nl;
else cout << res << nl;
}
}
}
int32_t main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
solve();
return 0;
}
