#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

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

const int NMAX = 100001;
int N, dist, ult;
bool viz[NMAX];
vector<int> lista[NMAX];

void DFS(int x, int niv)
{
    if(niv > dist)
    {
        dist = niv;
        ult = x;
    }
    viz[x] = true;
    for(auto &it : lista[x])
        if(viz[it] == false)
            DFS(it, niv + 1);
}
int main()
{
    int x, y;
    f >> N;
    for(int i = 1; i < N; i++)
    {
        f >> x >> y;
        lista[x].push_back(y);
        lista[y].push_back(x);
    }
    DFS(1, 1);
    dist = 0;
    for(int i = 1; i <= N; i++)
        viz[i] = false;
    DFS(ult, 1);
    g << dist;
    return 0;
}