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

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

vector <int> L[100005];
int d[100005], n, p;

void BFS(int k)
{
    queue <int> q;
    for (int i = 1; i <= n; i++)
        d[i] = 2e9;
    d[k] = 1;
    q.push(k);
    while (!q.empty())
    {
        k = q.front();
        q.pop();
        for (int e : L[k])
            if (d[e] > d[k] + 1)
            {
                d[e] = d[k] + 1;
                q.push(e);
            }
    }
    p = 0;
    for (int i = 1; i <= n; i++)
        if (d[p] < d[i])
            p = i;
}

int main()
{
    int i, x, y;
    fin >> n;
    for (i = 1; i < n; i++)
    {
        fin >> x >> y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    BFS(1);
    BFS(p);
    fout << d[p] << "\n";
    return 0;
}