#define MAX_N 100000

#include <fstream>
#include <list>
#include <algorithm>
using namespace std;

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

int n, rasp;
list<int> G[MAX_N + 1];

int Df(int nod);

int main()
{
    fin >> n;
    for (int i = 0, x, y; i < (n - 1); ++i)
    {
        fin >> x >> y;
        G[x].push_back(y);
    }

    Df(1);

    fout << rasp + 1;

    fin.close();
    fout.close();
    return 0;
}

int Df(int nod)
{
    int res = 0;

    for (int vecin : G[nod])
    {
        int resv = Df(vecin);
        rasp = max(rasp, res + resv + 1);
        res = max(res, resv + 1);
    }

    return res;
}