#include <bits/stdc++.h>
using namespace std;
template <typename T, bool maximum_mode = false>
struct RMQ {
  int n = 0, levels = 0;
  vector<T> values;
  vector<vector<int>> range_low;
  RMQ(const vector<T> &_values = {}) {
    if (!_values.empty()) build(_values);
  }
  static int largest_bit(int x) { return 31 - __builtin_clz(x); }
  int better_index(int a, int b) const {
    return (maximum_mode ? values[b] < values[a] : values[a] < values[b]) ? a
                                                                          : b;
  }
  void build(const vector<T> &_values) {
    values = _values;
    n = values.size();
    levels = largest_bit(n) + 1;
    range_low.resize(levels);
    for (int k = 0; k < levels; k++) range_low[k].resize(n - (1 << k) + 1);
    for (int i = 0; i < n; i++) range_low[0][i] = i;
    for (int k = 1; k < levels; k++)
      for (int i = 0; i <= n - (1 << k); i++)
        range_low[k][i] = better_index(range_low[k - 1][i],
                                       range_low[k - 1][i + (1 << (k - 1))]);
  }
  int query_index(int a, int b) const {
    assert(0 <= a && a < b && b <= n);
    int level = largest_bit(b - a);
    return better_index(range_low[level][a],
                        range_low[level][b - (1 << level)]);
  }
  T query_value(int a, int b) const { return values[query_index(a, b)]; }
};
struct LCA {
  int n = 0;
  vector<vector<int>> adj;
  vector<int> parent, depth, subtree_size;
  vector<int> euler, first_occurrence;
  vector<int> tour_start, tour_end, tour_list, postorder;
  vector<int> heavy_root;
  RMQ<int> rmq;
  LCA(int _n = 0) { init(_n); }
  LCA(const vector<vector<int>> &_adj) { init(_adj); }
  void init(int _n) {
    n = _n;
    adj.assign(n, {});
    parent.resize(n);
    depth.resize(n);
    subtree_size.resize(n);
    first_occurrence.resize(n);
    tour_start.resize(n);
    tour_end.resize(n);
    tour_list.resize(n);
    postorder.resize(n);
    heavy_root.resize(n);
  }
  void init(const vector<vector<int>> &_adj) {
    init(_adj.size());
    adj = _adj;
  }
  void add_edge(int a, int b) {
    adj[a].push_back(b);
    adj[b].push_back(a);
  }
  void dfs(int node, int par) {
    parent[node] = par;
    depth[node] = par < 0 ? 0 : depth[par] + 1;
    subtree_size[node] = 1;
    if (par >= 0)
      adj[node].erase(find(adj[node].begin(), adj[node].end(), par));
    for (int &child : adj[node]) {
      dfs(child, node);
      subtree_size[node] += subtree_size[child];
    }
    sort(adj[node].begin(), adj[node].end(),
         [&](int a, int b) { return subtree_size[a] > subtree_size[b]; });
  }
  int tour, post_tour;
  void tour_dfs(int node, bool heavy) {
    heavy_root[node] = heavy ? heavy_root[parent[node]] : node;
    first_occurrence[node] = euler.size();
    euler.push_back(node);
    tour_list[tour] = node;
    tour_start[node] = tour++;
    bool heavy_child = true;
    for (int child : adj[node]) {
      tour_dfs(child, heavy_child);
      euler.push_back(node);
      heavy_child = false;
    }
    tour_end[node] = tour;
    postorder[node] = post_tour++;
  }
  void build() {
    parent.assign(n, -1);
    for (int i = 0; i < n; i++)
      if (parent[i] < 0) dfs(i, -1);
    tour = post_tour = 0;
    for (int i = 0; i < n; i++)
      if (parent[i] < 0) {
        tour_dfs(i, false);
        euler.push_back(-1);
      }
    assert((int)euler.size() == 2 * n);
    vector<int> euler_depths;
    for (int node : euler)
      euler_depths.push_back(node < 0 ? node : depth[node]);
    rmq.build(euler_depths);
  }
  pair<int, int> find_farthest(int node, int par, int path) const {
    pair<int, int> current = {path, node};
    for (int neighbor : adj[node])
      if (neighbor != par)
        current = max(current, find_farthest(neighbor, node, path + 1));
    return current;
  }
  pair<int, pair<int, int>> get_diameter() const {
    int u = find_farthest(0, -1, 0).second;
    pair<int, int> farthest = find_farthest(u, -1, 0);
    int v = farthest.second;
    return {farthest.first, {u, v}};
  }
  int get_lca(int a, int b) const {
    a = first_occurrence[a];
    b = first_occurrence[b];
    if (a > b) swap(a, b);
    return euler[rmq.query_index(a, b + 1)];
  }
  bool is_ancestor(int a, int b) const {
    return tour_start[a] <= tour_start[b] && tour_start[b] < tour_end[a];
  }
  bool on_path(int x, int a, int b) const {
    int anc = get_lca(a, b);
    return is_ancestor(anc, x) && (is_ancestor(x, a) || is_ancestor(x, b));
  }
  int get_dist(int a, int b) const {
    return depth[a] + depth[b] - 2 * depth[get_lca(a, b)];
  }
  int child_ancestor(int a, int b) const {
    assert(a != b);
    assert(is_ancestor(a, b));
    int child =
        euler[rmq.query_index(first_occurrence[a], first_occurrence[b] + 1) +
              1];
    assert(is_ancestor(child, b));
    return child;
  }
};
int N;
LCA lca;
vector<vector<int>> adj;
vector<vector<long long>> dp;
long long solve(int a, int b) {
  assert(a != b);
  if (a > b) swap(a, b);
  long long &ans = dp[a][b];
  if (ans >= 0) return ans;
  int a_size = lca.subtree_size[a], b_size = lca.subtree_size[b];
  if (lca.is_ancestor(a, b))
    a_size = N - lca.subtree_size[lca.child_ancestor(a, b)];
  else if (lca.is_ancestor(b, a))
    b_size = N - lca.subtree_size[lca.child_ancestor(b, a)];
  ans = 0;
  for (int neighbor : adj[a])
    if (lca.get_dist(neighbor, b) > lca.get_dist(a, b))
      ans = max(ans, solve(neighbor, b));
  for (int neighbor : adj[b])
    if (lca.get_dist(a, neighbor) > lca.get_dist(a, b))
      ans = max(ans, solve(a, neighbor));
  ans += a_size * b_size;
  return ans;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  cin >> N;
  adj.assign(N, {});
  for (int i = 0; i < N - 1; i++) {
    int u, v;
    cin >> u >> v;
    u--;
    v--;
    adj[u].push_back(v);
    adj[v].push_back(u);
  }
  lca.init(adj);
  lca.build();
  dp.assign(N, vector<long long>(N, -1));
  long long best = 0;
  for (int i = 0; i < N; i++)
    if (lca.parent[i] >= 0) best = max(best, solve(i, lca.parent[i]));
  cout << best << '\n';
}
