#include <fstream>
#include <vector>
#include <queue>

using namespace std;

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

const int Nmax=100005;
int N, dmax, dist[Nmax], ultimul;

vector < int > listaAdiacenta[Nmax];
queue < int > coada;

void Read()
{
    fin >> N;
    for (int i=1; i<=N-1; i++)
    {
        int x, y;
        fin >> x >> y;
        listaAdiacenta[x].push_back(y);
        listaAdiacenta[y].push_back(x);
    }
    fin.close();
}

void BFS(int nod)
{
    coada.push(nod);
    for (int i=1; i<=Nmax; i++)
        dist[i]=0;
    dist[nod]=1;
    while (!coada.empty())
    {
        int nodCurent=coada.front();
        coada.pop();
        for (int i=0; i<listaAdiacenta[nodCurent].size(); i++)
        {

            if (dist[listaAdiacenta[nodCurent][i]]==0)
            {
                dist[listaAdiacenta[nodCurent][i]]=dist[nodCurent]+1;
                coada.push(listaAdiacenta[nodCurent][i]);
                dmax=dist[listaAdiacenta[nodCurent][i]];
                ultimul=listaAdiacenta[nodCurent][i];
            }
        }
    }
}

void Rezolvare()
{
    BFS(1);
    BFS(ultimul);
}

void Print()
{
    fout << dmax << "\n";
    fout.close();
}

int main()
{
    Read();
    Rezolvare();
    Print();
}