#include <iostream>
#include <fstream>
#include <vector>
#include<queue>
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
const int NMax=100005;
int N,Use[NMax],Dist[NMax],Sol;
vector<int>G[NMax];
queue <int> Q;

void read()
{
    fin>>N;
    for(int i=1;i<=N-1;++i)
    {
        int x,y;
        fin>>x>>y;
        G[x].push_back(y);
         G[y].push_back(x);

    }
}






void Solve()
{
    int Last;
    Q.push(1);
    Use[1] = 1;
    while(!Q.empty())
    {
        int Nod = Q.front();    Q.pop();
        Last = Nod;

        for(int i = 0 ; i < (int) G[Nod].size() ; ++i)
        {
            int Vecin = G[Nod][i];
            if(!Use[Vecin])
            {
                Use[Vecin] = 1;
                Q.push(Vecin);
            }
        }
    }

    Q.push(Last);
    Use[Last] = 2;
    Dist[Last] = 1;

    while(!Q.empty())
    {
        int Nod = Q.front();    Q.pop();

        for(int i = 0 ; i < (int) G[Nod].size() ; ++i)
        {
            int Vecin = G[Nod][i];
            if(Use[Vecin] != 2)
            {
                Dist[Vecin] = Dist[Nod] + 1;
                Use[Vecin] = 2;
                Q.push(Vecin);
                Sol = max(Sol,Dist[Vecin]);
            }
        }
    }
}
int main()
{
    read();
    Solve();

 fout<<Sol<<" ";
   return 0;
}