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

using namespace std;
const int NMAX=100000;

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

int N,diam,ult;
bool viz[NMAX+1];
vector<int> lista[NMAX+1];

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

void clean(){
    for(int i=1;i<=N;i++)
        viz[i]=0;
}

int main()
{
    citire();
    DFS(1,1);
    clean();
    DFS(ult,1);
    g << diam;
    return 0;
}