#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <cstring>
#define VMAX 100000

using namespace std;

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

vector <int> adj[VMAX];
int d[VMAX];
bool visited[VMAX];
int V, x, y;

pair <int, int> furthestNode(int starting_point)
{
    int u, last = starting_point;
    queue <int> q;
    for (int i = 0; i < V; ++i) d[i] = 0, visited[i] = false;
    q.push(starting_point);
    d[starting_point] = 1;
    visited[starting_point] = true;

    while (!q.empty())
    {
        u = q.front(), q.pop();
        for (auto w:adj[u])
            if (visited[w] == false)
            {
                visited[w] = true;
                d[w] = d[u] + 1;
                last = w;
                q.push(w);
            }
    }

    return {last, d[last]};
}

int main()
{
    fin >> V;

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

    auto furthest_from_origin = furthestNode(0);
    fout << furthestNode(furthest_from_origin.first).second;

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