#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int MN = 1e6;
vector<vector<int>> G(MN);
int N;
vector<int> dp1(MN, 0);
vector<int> dist(MN, 0);
void dfs(int v, int par) {
	for (auto nv : G[v]) {
		if (nv == par) continue;
		dfs(nv, v);
		dist[nv] = dist[v] + 1;
		dp1[v] = max(dp1[v], dp1[nv]+1);
	}
}
vector<vector<int>> DP(MN, vector<int>(2, -1));

int res = 1;
void dfs2(int v,int par) {
	multiset<int> st;
//	cout << v<< " " << DP[v][0] << " " << DP[v][1] << endl;
	map<int, int> cnt;
	for (auto nv : G[v]) {
		if (nv == par) continue;
		st.insert(dp1[nv]+1);
		cnt[dp1[nv]+1]++;
	}
	res = max(res, dist[v]+1);
	int dmx = max(DP[v][0], DP[v][1]);
	if (dmx != -1) {
		res = max(res, dmx+1);
	}
	for (auto v : cnt) {
		int d = v.first;int c = v.second;
		if (d <= dmx) {
			res = max(res, 1 + (d*(c+1)));
		}
	}
	for (auto nv : G[v]) {
		if (nv == par) continue;
		st.erase(st.find(dp1[nv] + 1));
		//0
		if (!st.empty()) DP[nv][0] = 1 + (*st.rbegin());
		//1
		if (DP[v][0] != -1) DP[nv][1] = 1 + DP[v][0];
		if (DP[v][1] != -1) DP[nv][1] = max(DP[nv][1], 1 + DP[v][1]);
		st.insert(dp1[nv] + 1);
		dfs2(nv, v);
	}
}
int main() {
	cin >> N;
	for (int i = 0;i < N-1;i++) {
		int u, v;cin >> u >> v;
		u--;v--;
		G[u].push_back(v);
		G[v].push_back(u);
	}
	dfs(0, 0);
	dfs2(0, 0);
	cout << res << endl;
}