#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#define MAX 100001

using namespace std;

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

int n;

vector <int> G[MAX];
int grad[MAX];
int d1[MAX];
int d2[MAX];

int FrunzaStart;
queue <int> q;

int f;
int maxim;

int ans;

void read()
{
    fin >> n;
    for (int i = 1; i < n; i++)
    {
        int x, y;
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
        grad[x]++;
        grad[y]++;
    }
    for (int i = 1; i <= n; i++)
    {
        if (grad[i] == 1)
        {
            FrunzaStart = i;
            break;
        }
    }
}

void bfs1()
{
    q.push(FrunzaStart);
    for (int i = 1; i <= n; i++)
        d1[i] = -1;
    d1[FrunzaStart] = 0;
    while (!q.empty())
    {
        int nod = q.front();
        q.pop();
        for (unsigned int i = 0; i < G[nod].size(); i++)
        {
            int vecin = G[nod][i];
            if (d1[vecin] == -1)
            {
                d1[vecin] = d1[nod] + 1;
                if (d1[vecin] > maxim)
                {
                    maxim = d1[vecin];
                    f = vecin;
                }
                q.push(vecin);
            }
        }
    }
}

void bfs2()
{
    for (int i = 1; i <= n; i++)
        d2[i] = -1;
    d2[f] = 1;
    q.push(f);
    while (!q.empty())
    {
        int nod = q.front();
        q.pop();
        for (unsigned int i = 0; i < G[nod].size(); i++)
        {
            int vecin = G[nod][i];
            if (d2[vecin] == -1)
            {
                d2[vecin] = d2[nod] + 1;
                q.push(vecin);
                if (d2[vecin] > ans)
                    ans = d2[vecin];
            }
        }
    }
}

int main()
{
    read();
    bfs1();
    bfs2();
    fout << ans;
    return 0;
}