#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], dep[NMAX];
int d[NMAX], s[NMAX], opt[NMAX];
int d2[NMAX], par[NMAX][17], mn[NMAX][17];
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;
dep[ch.v] = dep[nd]+1;
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];
tout[nd] = t-1;
}
void dfs2(int nd, int p = -1) {
par[nd][0] = p; mn[nd][0] = (p == -1?inf:d2[p]);
rep(i, 1, 17) {
if (par[nd][i-1] == -1)break;
par[nd][i] = par[par[nd][i-1]][i-1];
mn[nd][i] = min(mn[nd][i-1], mn[par[nd][i-1]][i-1]);
}
for (auto ch: g[nd]) {
if (ch.v == p)continue;
dfs2(ch.v, nd);
}
}
bool f(int l, int r, int x) {
if (l <= x && x <= r)return 1;
return 0;
}
void solve() {
memset(par, -1, sizeof par);
int n, ss, q, e;
cin >> n >> ss >> q >> e;
rep(i, 1, n+1) {
d[i] = d2[i] = inf;
//rep(j)
}
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);
dfs2(e);
//cout << d2[7] << nl;
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, dt = inf, len = dep[R]-dep[v], ro = R;
if (opt[R] != -1 && f(tin[v], tout[v], tin[opt[R]]))uc = s[R]-s[opt[R]];
int res = min(d[R], min(d[v]+s[R]-s[v], uc));
while (len) {
for (int i = 16; i >= 0; --i)
if (par[R][i] != -1 && dep[par[R][i]] >= dep[v]) {
dt = min(dt, mn[R][i]); len -= (1<<i);
R = par[R][i];
}
}
res = min(res, dt+s[ro]);
//cout << s[R] << " " << dt << nl;
if (res == inf)cout << "oo" << nl;
else cout << res << nl;
}
}
//cout << s[2] << nl;
//cout << d2[5] << " " << mn[2][0] << nl;
}
int32_t main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
solve();
return 0;
}
