#include <fstream>
#include <vector>
using namespace std;
int n, nrord[100100], last, diametru;
vector <int> G[100100];
bool viz[100100];

inline void DFS(int x)
{
	viz[x] = true;
	vector <int>::iterator it;
	for(it = G[x].begin(); it != G[x].end(); ++it)
	{
		if(!viz[*it])
		{
			nrord[*it] = nrord[x] + 1;
			if(nrord[*it] > nrord[last])
				last = *it;
			DFS(*it);
		}
	}
}

inline void DFS2(int x)
{
	viz[x] = true;
	vector <int>::iterator it;
	for(it = G[x].begin(); it != G[x].end(); ++it)
	{
		if(!viz[*it])
		{
			nrord[*it] = nrord[x] + 1;
			diametru = max(diametru, nrord[*it] + 1);
			DFS2(*it);
		}
	}
}

int main()
{
	int i, x, y;
	ifstream fin("darb.in");
	fin >> n;
	for(i = 1; i < n; ++i)
	{
		fin >> x >> y;
		G[x].push_back(y);
		G[y].push_back(x);
	}
	fin.close();
	
	last = 1;
	DFS(1);
	for(i = 1; i <= n; ++i)
	{
		viz[i] = false;
		nrord[i] = 0;
	}
	DFS2(last);
	
	ofstream fout("darb.out");
	fout << diametru << "\n";
	fout.close();
	return 0;
}