#include <fstream>
#include <vector>

using namespace std;
const int NMAX = 100001;

int N, diam, ult;
bool viz[NMAX];
vector <int> lista[NMAX];

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

void citire()
{
    int x, y;
    in >> N;
    for(int i = 1; i < N; i++)
    {
        in >> x >> y;
        lista[x].push_back(y);
        lista[y].push_back(x);
    }
}

void DFS(int x, int niv)
{
    if(niv > diam)
    {
        diam = niv;
        ult = x;
    }
    viz[x] = 1;
    for(auto &it : lista[x])
        if(viz[it] == 0)
        DFS(it, niv + 1);
}

int main()
{
    citire();
    DFS(1, 1);
    for(int i = 1; i <= N; i++)
        viz[i] = 0;
    DFS(ult, 1);
    out << diam;
    in.close();
    out.close();
    return 0;
}