#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int mxN = 1e5 + 100;
const ll INF = 1e18;
vector<pair<int, int>> adj[mxN];
int par[mxN], depth[mxN], head[mxN], heavy[mxN], sz[mxN], tin[mxN], tout[mxN], st[mxN], t = -1, t2 = -1;
ll dp[mxN], path_sum[mxN], seg[mxN * 4], lt[mxN];
struct seg_tree {
void build(int node, int start, int end) {
if (start == end) {
seg[node] = lt[start];
return;
}
int mid = (start + end) / 2;
build(node * 2 + 1, start, mid);
build(node * 2 + 2, mid + 1, end);
seg[node] = min(seg[node * 2 + 1], seg[node * 2 + 2]);
}
ll query(int node, int start, int end, int l, int r) {
if (start > r || end < l) return INF;
if (start >= l && end <= r) return seg[node];
int mid = (start + end) / 2;
return min(query(node * 2 + 1, start, mid, l, r),
query(node * 2 + 2, mid + 1, end, l, r));
}
} tr;
struct hld {
void dfs(int u = 1, int p = 0) {
depth[u] = depth[p] + 1;
par[u] = p;
sz[u] = 1;
tin[u] = ++t2;
for (auto it : adj[u]) {
int v = it.first, w = it.second;
if (v != p) {
path_sum[v] = path_sum[u] + w;
dfs(v, u);
dp[u] = min(dp[u], dp[v] + w);
sz[u] += sz[v];
if (sz[heavy[u]] < sz[v]) {
heavy[u] = v;
}
}
}
tout[u] = ++t2;
}
void dfs_hld(int u = 1, int chain = 1, int p = 0) {
head[u] = chain;
lt[++t] = dp[u] - path_sum[u];
st[u] = t;
if (heavy[u]) {
dfs_hld(heavy[u], chain, u);
}
for (auto it : adj[u]) {
int v = it.first;
if (v != p && heavy[u] != v) {
dfs_hld(v, v, u);
}
}
}
bool subtree(int u, int v) {
return tin[v] >= tin[u] && tout[v] <= tout[u];
}
ll query(int u, int v) {
ll ans = INF;
while (head[u] != head[v]) {
if (depth[head[u]] < depth[head[v]])
swap(u, v);
ans = min(ans, tr.query(0, 0, t, st[head[u]], st[u]));
u = par[head[u]];
}
if (st[u] > st[v]) swap(u, v);
ans = min(ans, tr.query(0, 0, t, st[u], st[v]));
return ans;
}
} hld;
int main() {
ios_base::sync_with_stdio(0);
cin.tie(nullptr); cout.tie(nullptr);
int n, s, q, e;
cin >> n >> s >> q >> e;
vector<pair<int, int>> edge;
for (int i = 0; i < n - 1; ++i) {
int u, v, w;
cin >> u >> v >> w;
adj[u].push_back({v, w});
adj[v].push_back({u, w});
edge.emplace_back(u, v);
}
for (int i = 1; i <= n; ++i) {
dp[i] = INF;
}
for (int i = 0; i < s; ++i) {
int u;
cin >> u;
dp[u] = 0;
}
hld.dfs(e, 0);
hld.dfs_hld(e, e, 0);
tr.build(0, 0, t);
while (q--) {
int edge_id, u;
cin >> edge_id >> u;
--edge_id;
int u1 = edge[edge_id].first;
int u2 = edge[edge_id].second;
if (hld.subtree(u1, u) && hld.subtree(u2, u) && u != e) {
if (depth[u1] < depth[u2]) swap(u1, u2);
ll answer = hld.query(u, u1) + path_sum[u];
if (answer >= INF) {
cout << "oo\n";
} else {
cout << answer << "\n";
}
} else {
cout << "escaped\n";
}
}
return 0;
}
