#include <bits/stdc++.h>
using namespace std;
#define Task ""
struct __Init__ {
__Init__() {
cin.tie(nullptr)->sync_with_stdio(false);
if (fopen(Task".inp", "r")) {
freopen(Task".inp", "r", stdin);
freopen(Task".out", "w", stdout); }
}
} __init__;
using ll = long long;
#ifdef LOCAL
#define debug(x) cerr << "[" #x " = " << x << "]\n";
#else
#define debug(...)
#endif // LOCAL
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define fi first
#define se second
#define For(i, l, r) for (int i = (l); i <= (r); ++i)
#define Ford(i, r, l) for (int i = (r); i >= (l); --i)
#define Rep(i, n) For (i, 0, (n) - 1)
#define Repd(i, n) Ford (i, (n) - 1, 0)
template<class C> int isz(const C& c) { return c.size(); }
template<class T> bool chmin(T& a, const T& b) { if (a > b) { a = b; return true; } return false; }
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } return false; }
constexpr int eps = 1e-9;
constexpr int inf = 1e9;
constexpr ll linf = 1e18;
// =============================================================================
constexpr int maxN = 1e5 + 5;
constexpr int logN = 18;
struct Edge {
int u, v, c;
int other(int x) const {
return u ^ v ^ x;
}
};
int n, ns, nq, root;
vector<int> g[maxN];
Edge e[maxN];
int tin[maxN], tout[maxN], timer;
int par[maxN][logN];
int dep[maxN];
ll st[maxN][logN];
ll dist[maxN];
ll dp[maxN];
void Dfs(int u) {
tin[u] = ++timer;
for (int i : g[u]) {
int v = e[i].other(u);
if (v != par[u][0]) {
dist[v] = dist[u] + e[i].c;
dep[v] = dep[u] + 1;
par[v][0] = u;
Dfs(v);
chmin(dp[u], dp[v] + e[i].c);
}
}
tout[u] = ++timer;
}
bool isAnc(int u, int v) {
return tin[u] <= tin[v] && tout[v] <= tout[u];
}
signed main() {
cin >> n >> ns >> nq >> root;
For (i, 1, n - 1) {
int u, v, c; cin >> u >> v >> c;
e[i] = {u, v, c};
g[u].push_back(i);
g[v].push_back(i);
}
For (i, 1, n) dp[i] = linf;
For (i, 1, ns) {
int x; cin >> x;
dp[x] = 0;
}
Dfs(root);
For (i, 1, n) {
st[i][0] = dp[i] - dist[i];
}
For (j, 1, logN - 1) {
For (i, 1, n) {
int m = par[i][j - 1];
par[i][j] = par[m][j - 1];
st[i][j] = min(st[i][j - 1], st[m][j - 1]);
}
}
Rep (_, nq) {
int id, x; cin >> id >> x;
int u = e[id].u;
int v = e[id].v;
if (tin[u] > tin[v]) swap(u, v);
if (!isAnc(v, x)) {
cout << "escaped\n";
continue;
}
ll ans = linf;
int step = dep[x] - dep[v] + 1;
u = x;
Repd (i, logN) {
if (step >> i & 1) {
chmin(ans, st[u][i]);
u = par[u][i];
}
}
ans += dist[x];
if (ans >= linf) {
cout << "oo\n";
} else {
cout << ans << '\n';
}
}
}
/*
*/
