#include <bits/stdc++.h>
using namespace std;
using ll = long long;
constexpr int inf = 1e9;
using P = pair<int, int>;
template <typename T>
void printv(const vector<T> &v) {
  int sz = v.size();
  for (int i = 0; i < sz; i++) {
    cout << v[i] << " \n"[i == sz - 1];
  }
}
using Graph = vector<vector<int>>;
const int MAX_N = 3010;
Graph g(MAX_N);
vector<vector<int>> dist(MAX_N, vector<int>(MAX_N, inf));
vector<vector<int>> ch(MAX_N, vector<int>(MAX_N));
int dfs(int r, int cur, int pre) {
  ch[r][cur] = 1;
  for (auto nxt : g[cur]) {
    if (nxt == pre) continue;
    ch[r][cur] += dfs(r, nxt, cur);
  }
  return ch[r][cur];
}
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int n;
  cin >> n;
  vector<P> ps;
  for (int i = 0; i < n - 1; i++) {
    int u, v;
    cin >> u >> v;
    u--;
    v--;
    ps.push_back(P(u, v));
    g[u].push_back(v);
    g[v].push_back(u);
  }
  for (int i = 0; i < n; i++) {
    queue<int> que;
    que.push(i);
    dist[i][i] = 0;
    while (!que.empty()) {
      int v = que.front();
      que.pop();
      for (auto nxt : g[v]) {
        if (dist[i][nxt] != inf) continue;
        dist[i][nxt] = dist[i][v] + 1;
        que.push(nxt);
      }
    }
  }
  for (int i = 0; i < n; i++) {
    dfs(i, i, -1);
  }
  vector<vector<P>> cs(n);
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      cs[dist[i][j]].push_back(P(i, j));
    }
  }
  vector<vector<ll>> dp(n, vector<ll>(n));
  for (int d = 0; d < n - 1; d++) {
    for (auto p : cs[d]) {
      int u = p.first, v = p.second;
      for (auto nxt : g[u]) {
        if (dist[u][nxt] + dist[u][v] != dist[v][nxt]) continue;
        ll x = ch[nxt][v], y = ch[u][nxt];
        dp[nxt][v] = max(dp[nxt][v], dp[u][v] + x * y);
        dp[v][nxt] = max(dp[v][nxt], dp[u][v] + x * y);
      }
      for (auto nxt : g[v]) {
        if (dist[v][nxt] + dist[u][v] != dist[u][nxt]) continue;
        ll x = ch[nxt][u], y = ch[v][nxt];
        dp[nxt][u] = max(dp[nxt][u], dp[u][v] + x * y);
        dp[u][nxt] = max(dp[u][nxt], dp[u][v] + x * y);
      }
    }
  }
  ll ret = 0;
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) ret = max(ret, dp[i][j]);
  cout << ret << endl;
}
