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

using namespace std;
ifstream f("darb.in");
ofstream g("darb.out");
int n,m,s,poz,sol;
vector< vector <int> > v;
vector< int > a;
vector< bool > viz;
queue <int> coada;
void bfs()
{
    int nr,i,x,y;
    while(!coada.empty())
    {
        poz=x=coada.front();
        coada.pop();
        nr=v[x].size();
        for(i=0;i<nr;i++)
        {
            y=v[x][i];
            if(viz[y]==0)
            {
                coada.push(y);
                a[y]=a[x]+1;
                sol=max(sol,a[y]);
                viz[y]=1;
            }
        }
    }
}
int main()
{
    int i,x,y;
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);
    scanf("%d",&n);//f>>n;
    v.resize(n+2);
    for(i=1;i<n;i++)
    {
        scanf("%d %d",&x,&y);//f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    viz.resize(n+2);
    a.resize(n+2);
    coada.push(1);
    bfs();
    for(i=1;i<=n;i++)
        viz[i]=0,a[i]=0;
    coada.push(poz);
    bfs();
    printf("%d",sol+1);//g<<sol+1;
    return 0;
 }