#include <fstream>
#include <vector>
#include <queue>

using namespace std;

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

int n,last,sol,dist[100003],viz[100003];
vector<int>g[100003];
queue<int>coada;

void bfs(int nod)
{
    viz[nod]=1;
    dist[nod]=1;
    coada.push(nod);
    while(!coada.empty())
    {

        int x=coada.front();
        coada.pop();
        viz[x]=1;
        for(vector<int> :: iterator it=g[x].begin();it!=g[x].end();it++)
        {
            int next=*it;
            if(viz[next]==0)
            {
                dist[next]=dist[x]+1;
                last=next;
                sol=dist[next];
                coada.push(next);
            }
        }
    }
}

int main()
{

    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);
    }
    bfs(1);
    for(int i=1;i<=n;i++)
    {
        viz[i]=0;
        dist[i]=0;
    }
    bfs(last);
    fout<<sol;
}