#include <iostream>
#include <fstream>
#include <vector>
#include <cstring>
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
#define MAX 100010

typedef vector <int> :: iterator iter;
vector <int> G[MAX];

int viz[MAX];

void df(int nod)
{
    for(iter it = G[nod].begin() ; it != G[nod].end() ; it++)
    {
        if(!viz[*it])
        {
            viz[*it] = viz[nod] + 1;
            df(*it);
        }
    }
}

int main()
{
    int n, i, x, y, mx;
    fin >> n;
    for(i = 1 ; i < n ; i++)
    {
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    viz[1] = 1;
    df(1);
    mx = 1;
    for(i = 1 ; i <= n ; i++)
        if(viz[i] > viz[mx])
            mx = i;
    memset(viz, 0, sizeof(viz));
    viz[mx] = 1;
    df(mx);
    mx = 1;
    for(i = 1 ; i <= n ; i++)
    {
        if(viz[i] > viz[mx])
            mx = i;
    }
    fout << viz[mx] << "\n";
}