#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
#define MAX 100010

vector <int> G[MAX];
queue <int> coada;
int dist[MAX];

int bfs(int nod)
{
    coada.push(nod);
    dist[nod]=1;
    while(coada.size())
    {
        nod=coada.front();
        coada.pop();
        for(int i=0;i<G[nod].size();i++)
        {
            int g=G[nod][i];
            if(!dist[g])
            {
                dist[g]=dist[nod]+1;
                coada.push(g);
            }
        }
    }
    return nod;
}

int main()
{
    int n, x, y, i, nod;
    fin>>n;
    for(i=1;i<n;i++)
    {
        fin>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    nod=bfs(1);
    for(i=1;i<=n;i++)
        dist[i]=0;
    fout<<dist[bfs(nod)]<<"\n";

}