#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll inf = 1e18;
bool chmin(ll &a, const ll &b) {
return a > b ? a = b, true : false;
}
void solve() {
int N, S, Q, E;
cin >> N >> S >> Q >> E;
E--;
vector<vector< array<int, 3> >> adj(N);
for(int i = 0; i < N - 1; i++) {
int A, B, W; cin >> A >> B >> W;
A--, B--;
adj[A].push_back({B, W, i});
adj[B].push_back({A, W, i});
}
vector<int> is_S(N);
for(int i = 0; i < S; i++) {
int v; cin >> v;
v--;
is_S[v] = 1;
}
vector jmp(N, vector(20, E));
vector mno(N, vector(20, inf));
vector<ll> cost(N), mn(N, inf), d(N);
vector<int> ind(N - 1), tin(N), tout(N);
{
int timer = 0;
auto dfs = [&](auto &&self, int v, int p) -> void {
if(is_S[v]) mn[v] = cost[v];
tin[v] = ++timer;
for(auto [to, w, i] : adj[v]) {
if(to == p) continue;
ind[i] = to;
cost[to] = cost[v] + w;
d[to] = d[v] + 1;
self(self, to, v);
chmin(mn[v], mn[to]);
}
tout[v] = timer;
};
dfs(dfs, E, E);
}
{
auto dfs = [&](auto &&self, int v, int p) -> void {
jmp[v][0] = p;
if(mn[v] != inf) mno[v][0] = mn[v] - 2 * cost[v];
if(v != p && mn[p] != inf) chmin(mno[v][0], mn[p] - 2 * cost[p]);
for(int i = 1; i < 20; i++) {
jmp[v][i] = jmp[ jmp[v][i - 1] ][i - 1];
mno[v][i] = min( mno[v][i - 1], mno[ jmp[v][i - 1] ][i - 1] );
}
for(auto [to, w, i] : adj[v]) {
if(to == p) continue;
self(self, to, v);
chmin(mn[v], mn[to]);
}
};
dfs(dfs, E, E);
}
auto upper = [&](int u, int v) {
return tin[v] >= tin[u] && tout[v] <= tout[u];
};
auto kth = [&](int u, int k) {
ll ans = inf;
if(mn[u] != inf) chmin(ans, mn[u] - 2 * cost[u]);
// cout << "cost: " << cost[u] << '\n';
for(int i = 0; i < 20; i++) {
if(k >> i & 1) {
// cout << mno[u][i] << ' ';
chmin(ans, mno[u][i]);
u = jmp[u][i];
}
}
// cout << '\n';
return ans;
};
// for(auto &x : ind) cout << x + 1 << ' ';
// cout << '\n';
while(Q--) {
int I, R; cin >> I >> R;
I--, R--;
int v = ind[I];
// cout << '\n';
// cout << v + 1 << ' ' << R + 1 << '\n';
if(d[R] < d[v] || !upper(v, R)) {
cout << "escaped" << '\n';
continue;
}
ll ans = kth(R, d[R] - d[v]);
ll res = ans + cost[R];
if(res >= inf) {
cout << "oo" << '\n';
continue;
}
cout << res << '\n';
}
}
signed main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
solve();
}
