#include <bits/stdc++.h>

using namespace std;

///diametrul arborelui

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

int n, m, nod, dmax, x, y;
vector < int > L[100005];
int viz[100005], d[100005];

void Citire()
{
    fin >> n;
    while(fin >> x >> y)
    {
        L[x].push_back(y);
        L[y].push_back(x);
    }
}

void DFS(int k)
{
    viz[k] = 1;
    for(auto i : L[k])
        if(!viz[i])
        {
            d[i] = 1 + d[k];
            if(d[i] > dmax)
            {
                dmax = d[i];
                nod = i;
            }
            DFS(i);
        }
}

int main()
{
    Citire();
    DFS(1);
    dmax = 0;
    for(int i = 1; i <= n; i++)
    {
        d[i] = 0;
        viz[i] = 0;
    }
    DFS(nod);
    fout << dmax + 1;
    return 0;
}