#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int inf = 1e9 + 7;
const ll infll = 1e18;
template<typename T>
istream &operator>>(istream &is, vector<T> &a) {
for (auto &i : a) {
is >> i;
}
return is;
}
struct Edge {
int to, w;
};
struct BinaryJumps {
static const int lg = 17;
vector<vector<int>> up;
vector<vector<ll>> dp;
BinaryJumps() {}
BinaryJumps(int n) {
up.resize(lg, vector<int>(n, -1));
dp.resize(lg, vector<ll>(n, infll));
}
void add_leaf(int v, int p, int w) {
up[0][v] = p;
dp[0][v] = w;
for (int i = 1; i < lg; ++i) {
if (up[i - 1][v] != -1) {
up[i][v] = up[i - 1][up[i - 1][v]];
dp[i][v] = min(dp[i - 1][v], dp[i - 1][up[i - 1][v]]);
}
}
}
ll la(int v, const function<bool(int)> &func) {
ll ans = infll;
for (int i = lg - 1; i >= 0; --i) {
if (up[i][v] == -1) {
continue;
}
if (func(up[i][v])) {
ans = min(ans, dp[i][v]);
v = up[i][v];
}
}
return ans;
}
};
vector<vector<Edge>> g;
BinaryJumps tr;
vector<ll> d, dp;
vector<int> tin, tout;
int timer = 0;
void dfs1(int v, int p = -1) {
tin[v] = timer++;
for (auto [u, w] : g[v]) {
if (u != p) {
d[u] = d[v] + w;
dfs1(u, v);
dp[v] = min(dp[v], dp[u] + w);
}
}
tout[v] = timer;
}
void dfs2(int v, int p = -1) {
if (dp[v] < infll) {
dp[v] -= d[v];
}
for (auto [u, w] : g[v]) {
if (u != p) {
tr.add_leaf(u, v, dp[v]);
dfs2(u, v);
}
}
}
bool is_anc(int p, int v) {
return tin[p] <= tin[v] && tout[v] <= tout[p];
}
int32_t main() {
#ifdef LOCAL
freopen("/tmp/input.txt", "r", stdin);
#else
ios::sync_with_stdio(false);
cin.tie(nullptr);
#endif
int n, s, q, e;
cin >> n >> s >> q >> e;
--e;
g.resize(n);
vector<array<int, 3>> edg(n - 1);
for (int i = 0; i < n - 1; ++i) {
int u, v, w;
cin >> u >> v >> w;
--u, --v;
g[u].push_back({v, w});
g[v].push_back({u, w});
edg[i] = {u, v, w};
}
dp.resize(n, infll);
for (int i = 0; i < s; ++i) {
int v;
cin >> v;
--v;
dp[v] = 0;
}
d.resize(n);
tin.resize(n);
tout.resize(n);
dfs1(e);
tr = BinaryJumps(n);
dfs2(e);
while (q--) {
int i, v;
cin >> i >> v;
--i, --v;
auto [a, b, c] = edg[i];
if (d[a] > d[b]) {
swap(a, b);
}
if (!is_anc(b, v)) {
cout << "escaped\n";
continue;
}
ll ans = min(dp[v], tr.la(v, [&](int u) {
return !is_anc(u, a);
}));
if (ans == infll) {
cout << "oo\n";
} else {
cout << ans + d[v] << "\n";
}
}
return 0;
}
