#include <iostream>
#include <fstream>
#include <queue>
#include <algorithm>

using namespace std;

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

#define nmax 100005

vector <int> v[nmax];

int viz[nmax],lvl[nmax],n,x,y,maxim=1,node,vizf[nmax],niv[nmax];

queue <int> Queue;

void DFS(int viz[], int lvl[], int nod)
{
    viz[nod]=1;
    lvl[nod]=1;
    Queue.push(nod);
    while(!Queue.empty())
    {
        int k=Queue.front();
        vector <int> ::iterator it;
        for(it=v[k].begin();it!=v[k].end();it++)
        {
            if(!viz[*it])
            {
                viz[*it]=1;
                lvl[*it]=lvl[k]+1;
                if(lvl[*it]>maxim)
                {
                    maxim=lvl[*it];
                    node=*it;
                }
                Queue.push(*it);
            }
        }
        Queue.pop();
    }
}

int main()
{
    fin>>n;
    for(int i=1;i<=n-1;i++)
    {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    maxim=1;
    node=1;
    DFS(viz,lvl,1);
    maxim=1;
    DFS(vizf,niv,node);
    fout<<maxim<<'\n';
}