#include <iostream>
#include <fstream>

using namespace std;

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

const int maxVal = 100001;

struct nod
{
    int info;
    nod * urm;
}* v[maxVal];

void adaugare (int x, int y)
{
    nod * t = new nod;
    t -> info = y;
    t -> urm = v[x];
    v[x] = t;
}

void dfs (int x, int h, int &hMax, int vizitat[], int &nodMax)
{
    vizitat[x] = 1;
    nod * t = v[x];
    while (t)
    {
        if (vizitat[t -> info] == 0)
            dfs (t -> info, h+1, hMax, vizitat, nodMax);
        t = t -> urm;
    }
    if (h > hMax)
    {
        hMax = h;
        nodMax = x;
    }
}

int main()
{
    int n, x, y;
    fin >> n;
    while (fin >> x >> y)
    {
        adaugare (x, y);
        adaugare (y, x);
    }
    int hMax = 0;
    int vizitat[maxVal] = {0};
    int nodMax;
    dfs(1, 1, hMax, vizitat, nodMax);
    for (int i = 1; i <= n; i++)
        vizitat[i] = 0;
    hMax = 0;
    dfs(nodMax, 1, hMax, vizitat, nodMax);
    fout << hMax;
    return 0;
}