#include <fstream>
#include <iostream>
#include <vector>
#include <bitset>
using namespace std;

const int NMAX = 1e5 + 2;

vector <int> g[NMAX];

bitset <NMAX> viz;

int x, y, n, darb, start;

void DFS(int x, int niv)
{
	if (niv > darb) 
	{
		darb = niv;
		start = x;
	}
	viz[x] = 1;
	for (size_t i = 0; i < g[x].size(); ++i)
		if (viz[g[x][i]] == 0) DFS(g[x][i], niv + 1);
}

ifstream fin("darb.in");
ofstream fout("darb.out");

int main()
{
	fin >> n;
	for (int i = 1; i < n; ++i)
	{
		fin >> x >> y;
		g[x].push_back(y);
		g[y].push_back(x);
	}
	DFS(1, 1);
	viz.reset();
	darb = 0;
	DFS(start, 1);
	fout << darb << "\n";
	return 0;
}