#include <bits/stdc++.h>

using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
vector <int> L[100005];
int viz[100005], n, drum[100005];
void Citire()
{
    int x, y;

    fin >> n;
    for(int i = 1; i <= n; i++)
    {
        fin >> x >> y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
}

void DFS(int nod)
{
    viz[nod] = 1;

    for(auto i : L[nod])
    {
        if(!viz[i])
        {
            drum[i] = drum[nod] + 1;
            DFS(i);
        }
    }
}

void Rez()
{
    drum[1] = 1;
    DFS(1);

    int maxim = -1, nodm;
    for(int i = 1; i <= n; i++)
    {
        if(drum[i] > maxim)
        {
            maxim = drum[i];
            nodm = i;
        }
        viz[i] = 0;
        drum[i] = 0;
    }

    drum[nodm] = 1;
    DFS(nodm);

    maxim = -1;
    for(int i = 1; i <= n; i++)
        maxim = max(maxim, drum[i]);
    fout << maxim << "\n";
}
int main()
{
    Citire();
    Rez();
    return 0;
}