#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,Nr[NMAX];
bool viz[NMAX];
vector <int> lista[NMAX];
void citire()
{
    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);
    }
}
void DFS(int x,int h)
{
    if(h>dist)
    {
        dist=h;
        ult=x;
    }
    viz[x]=1;
    for(unsigned int i=0; i<lista[x].size(); i++)
        if(viz[lista[x][i]]==0)
        {
            DFS(lista[x][i],h+1);
        }
}
int main()
{
    citire();
    DFS(1,1);
    for(int i=1; i<=N; i++)
        viz[i]=0;
    DFS(ult,1);
    g<<dist<<'\n';
    return 0;
}