#include <bits/stdc++.h>

using namespace std;

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

vector <int> h[100003];
int n, m;
int viz[100003], d[100003];

void DFS (int k)
{
    viz[k] = 1;
    for (auto i : h[k])
        if (viz[i] == 0)
        {
            d[i] = 1 + d[k];
            DFS(i);
        }
}

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

int main()
{
    int M = -1, poz, i;
    Citire();
    DFS(1);
    for (i = 1; i <= n; i++)
        if (d[i] > M)
        {
            M = d[i];
            poz = i;
        }
    for (i = 1; i <= n; i++)
        d[i] = viz[i] = 0;
    DFS(poz);
    M = -1;
    for (i = 1; i <= n; i++)
        if (d[i] > M)
            M = d[i];
    fout << M + 1;

    return 0;
}