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

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

vector <int> G[100001];
int n;
int viz[100001];
int dist[100001];

void citire()
{
    fin >> n;

    int x, y;
    for(int i = 0; i < n - 1; ++i)
    {
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
}

int bfs(int x)
{
    queue <int> q;
    q.push(x);
    viz[x] = 1;
    int last = -1;

    while(!q.empty())
    {
        int el = q.front();
        last = el;
        q.pop();
        for(int i = 0; i < G[el].size(); ++i)
        {
            int to = G[el][i];
            if(!viz[to])
            {
                q.push(to);
                viz[to] = 1;
            }
        }
    }
    return last;
}

int distanta(int inc)
{
    queue <int> q;
    q.push(inc);
    dist[inc] = 1;
    int last = -1;

    while(!q.empty())
    {
        int el = q.front();
        last = el;
        q.pop();
        for(int i = 0; i < G[el].size(); ++i)
        {
            int to = G[el][i];
            if(!dist[to])
            {
                q.push(to);
                dist[to] = dist[el] + 1;
            }
        }
    }
    return dist[last];
}

int main()
{
    citire();
    int inc = bfs(1);
    fout << distanta(inc);
    return 0;
}