// In the name of the God
#include <bits/stdc++.h>
#define ll long long
#define int long long
#define pb push_back
#define F first
#define S second
#define mp make_pair
#define pii pair <int, int>
#define smin(x, y) (x) = min((x), (y))
#define smax(x, y) (x) = max((x), (y))
#define all(x) (x).begin(), (x).end()
using namespace std;
const int inf = (1e9+7)*(1e9+7);
const int mod = 998244353;
const int maxn = 1e5+5, lg = 17;
int n, s, q, e, t = 0, fr[maxn], to[maxn], in[maxn], out[maxn], h[maxn], mn[maxn], cost[maxn];
bool mark[maxn];
pii par[lg][maxn];
vector <pii> adj[maxn];
void dfs1(int v, int p) {
in[v] = t++;
mn[v] = (!mark[v])*inf;
for (pii ed : adj[v]) {
int u = ed.F;
if (u != p) {
h[u] = h[v]+1;
cost[u] = cost[v]+ed.S;
dfs1(u, v);
smin(mn[v], ed.S+mn[u]);
}
}
out[v] = t;
}
void dfs2(int v, int p) {
par[0][v] = mp(p, mn[v]-cost[v]);
for (int i = 1; i < lg; i++) {
par[i][v] = mp(par[i-1][par[i-1][v].F].F, min(par[i-1][v].S, par[i-1][par[i-1][v].F].S));
}
for (pii ed : adj[v]) {
int u = ed.F;
if (u != p) dfs2(u, v);
}
}
bool is(int v, int u) {
return in[v] <= in[u] and out[v] >= out[u];
}
int32_t main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> s >> q >> e;
for (int i = 1; i < n; i++) {
int v, u, w; cin >> v >> u >> w;
adj[--v].pb(mp(--u, w));
adj[u].pb(mp(v, w));
fr[i] = v, to[i] = u;
}
for (int i = 0; i < s; i++) {
int v; cin >> v; mark[--v] = 1;
}
dfs1(e, e), dfs2(e, e);
while (q--) {
int i, v; cin >> i >> v; v--;
int u = fr[i], z = to[i];
if (in[u] > in[z]) swap(u, z);
if (!is(z, v)) cout << "escaped\n";
else {
int ans = inf, d = cost[v], diff = (h[v]-h[u]);
for (int i = 0; i < lg; i++) {
if (diff&(1<<i)) {
smin(ans, d+par[i][v].S);
v = par[i][v].F;
}
}
if (ans == inf) cout << "oo\n";
else cout << ans << '\n';
}
}
return 0;
}
