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

ifstream f("darb.in");
ofstream g("darb.out");

const int NMAX = 100001;

int N, diam, ult;
bool viz[NMAX];
vector <int> lista[NMAX];

void citire()
{
    int x, y;
    f >> N;
    for (int i = 1 ; i < N ; i++)
    {
        f >> x >> y;
        lista[x].push_back(y);
        lista[y].push_back(x);
    }
}

void DFS(int x, int niv)
{
    if (niv > diam)
    {
        diam = niv;
        ult = x;
    }
    viz[x] = 1;
    for (auto &it : lista[x])
        if (viz[it] == 0)
        DFS(it, niv + 1);
}


int main()
{
    citire();
    DFS(1, 1);
    //diam = 0;
    for (int i = 1 ; i <= N ; i++)
        viz[i] = 0;
    DFS(ult, 1);
    g << diam;
    return 0;
}