#include<iostream>
#include<fstream>
#include<vector>
#include<queue>
#define NMax 100005
using namespace std;

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

int N,Sol;
int Use[NMax],Dist[NMax];

vector <int> G[NMax];
queue <int> Q;

void Read()
{
	fin>>N;

	for(int i = 1 ; i < N ; ++i)
	{
		int x,y;	fin>>x>>y;
		G[x].push_back(y);
		G[y].push_back(x);
	}
}

void Solve()
{
	int Last;

	Q.push(1);
	Use[1] = 1;

	while(!Q.empty())
	{
        int Nod = Q.front();	Q.pop();

        Last = Nod;

        for(int i = 0 ; i < (int) G[Nod].size() ; ++i)
		{
			int Vecin = G[Nod][i];
			if(!Use[Vecin])
			{
				Use[Vecin] = 1;
                Q.push(Vecin);
			}
		}
	}

    Q.push(Last);
    Use[Last] = 2;
    Dist[Last] = 1;

    while(!Q.empty())
	{
        int Nod = Q.front();	Q.pop();

        for(int i = 0 ; i < (int) G[Nod].size() ; ++i)
		{
			int Vecin = G[Nod][i];

			if(Use[Vecin] != 2)
			{
                Dist[Vecin] = Dist[Nod] + 1;
                Use[Vecin] = 2;
                Q.push(Vecin);
                Sol = max(Sol,Dist[Vecin]);
			}
		}
	}
}

void Print()
{
	fout<<Sol<<"\n";
}

int main()
{
	Read();
	Solve();
	Print();

	fin.close();
	fout.close();
	return 0;
}