#include "bits/extc++.h"
using namespace std;
template <typename T, typename... U>
void dbgh(const T& t, const U&... u) {
cerr << t;
((cerr << " | " << u), ...);
cerr << endl;
}
#ifdef DEBUG
#define dbg(...) \
cerr << "L" << __LINE__ << " [" << #__VA_ARGS__ << "]: "; \
dbgh(__VA_ARGS__)
#else
#define dbg(...)
#define cerr \
if (false) \
cerr
#endif
#define endl "\n"
#define long int64_t
#define sz(x) int(std::size(x))
int getDistance(int i, int j);
struct G {
map<pair<int, int>, int> cache;
int query(int u, int v) {
if (u > v) {
swap(u, v);
}
auto [it, inserted] = cache.insert({{u, v}, -1});
if (!inserted) {
return it->second;
}
return it->second = getDistance(u, v);
}
} G;
int hubDistance(int n, int tc_id) {
G = {};
auto farthest = [&](int u) -> int {
pair<int, int> ans {-1, 0};
for (int i = 0; i < n; i++) {
ans = max(ans, {G.query(u, i), i});
}
return ans.second;
};
int u1 = farthest(0), u2 = farthest(u1);
int u_hori[n], u_down[n];
for (int i = 0; i < n; i++) {
int d1 = G.query(u1, i), d2 = G.query(u2, i);
u_down[i] = (d1 + d2 - G.query(u1, u2)) / 2;
u_hori[i] = d1 - u_down[i];
}
int ans = 1e9;
for (int i = 0; i < n; i++) {
ans = min(ans, max(u_hori[i], G.query(u1, u2) - u_hori[i]));
}
return ans;
}
