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

using namespace std;

vector <int> G[100010];
int viz[100010];
int N, M;
int rez;
int distantaMaxima;
int nodAflatLaDistantaMaxima;

void Read()
{
    ifstream f("darb.in");
    f >> N;
    for (int i = 1; i <= N-1; ++ i)
    {
        int x, y;
        f >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    f.close();
}

void DFS(int node, int distanta)
{
    viz[node] = true;
    if (distanta > distantaMaxima)
    {
        distantaMaxima = distanta;
        nodAflatLaDistantaMaxima = node;
    }
    for (vector <int> :: iterator it = G[node].begin(); it != G[node].end(); ++ it)
        if (!viz[*it])
            DFS(*it, distanta + 1);
}

void Solve()
{
    distantaMaxima = -1;
    DFS(1, 0);

    for (int i = 1; i <= N; ++ i)
        viz[i] = false;
    distantaMaxima = -1;
    DFS(nodAflatLaDistantaMaxima, 0);
    rez = distantaMaxima + 1;
}

void Write()
{
    ofstream g("darb.out");
    g << rez << "\n";
    g.close();
}

int main()
{
    Read();
    Solve();
    Write();
    return 0;
}