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

using namespace std;

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

const int DIM = 100005;

int n,x,y,Dist[DIM],Max,Root;

vector <int> G[DIM];

void Read()
{
    fin>>n;
    for(int i=1;i<n;i++)
    {
        fin>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
}

queue <int> Q;

void BFS(int start)
{
    Q.push(start);
    Dist[start]=1;
    while(!Q.empty())
    {
        int nod=Q.front();
        if(Dist[nod]>Max)
        {
            Max=Dist[nod];
            Root=nod;
        }
        vector <int> ::iterator it;
        for(it=G[nod].begin();it!=G[nod].end();it++)
        {
            if(!Dist[*it])
            {
                Dist[*it]=Dist[nod]+1;
                Q.push(*it);
            }
        }
        Q.pop();
    }
}

int main()
{
    Read();
    BFS(1);
    memset(Dist,0,sizeof(Dist));
    BFS(Root);
    fout<<Max<<'\n';
}