/**

*/
#include<iostream>
#include<fstream>
#include<string.h>
#include<queue>
#include<vector>

using namespace std;

vector <int>G[100001];
queue <int>Q;
ifstream fin;
ofstream fout("darb.out");
int N,d[100001];

void Read()
{
    fin.open("darb.in");
    fin>>N;
    for(int i=1;i<N;i++)
    {
        int x,y;
        fin>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
}

void bfs(int nod)
{
    Q.push(nod);
    for(int i=1;i<=N;i++)
        d[i]=-1;
    d[nod]=0;
    while(!Q.empty())
    {
        int Nod;
        Nod=Q.front();Q.pop();
        for(int i=0;i<(int)G[Nod].size();i++)
        {
            if(d[G[Nod][i]]==-1)
            {
                d[G[Nod][i]]=d[Nod]+1;
                Q.push(G[Nod][i]);
            }
        }
    }
}
int main()
{
    int maxim=0,imax;
    Read();
    bfs(1);
    for(int i=1;i<=N;i++)
        if(d[i]>maxim){imax=i;maxim=d[i];}
    bfs(imax);
    for(int i=1;i<=N;i++)
        if(d[i]>maxim){maxim=d[i];}
    fout<<maxim+1;
    return 0;
}