#include <fstream>
#include <vector>
#include <queue>
#include <string.h>
using namespace std;
ifstream cin("darb.in");
ofstream cout("darb.out");
#define N_MAX 100001
#define NMAX 1000001
int n,v[N_MAX],ult,diam,contor[NMAX],x,y;

queue <int> q;
vector <int> graf[N_MAX];
void bfs(int nod)
{
    memset(contor,0,NMAX);
    memset(v,0,NMAX);
    q.push(nod);
    v[nod]=1;
    contor[nod]=1;
    int nc ,i;
    while(!q.empty())
    {
        nc=q.front();
        q.pop();
        for(i=0; i<graf[nc].size(); i++)
        {
            if(v[graf[nc][i]]==0)
            {
                v[graf[nc][i]]=1;
                q.push(graf[nc][i]);
                ult=graf[nc][i];
                contor[graf[nc][i]]=contor[nc]+1;
                diam=contor[graf[nc][i]];
            }
        }
    }
}
int main()
{
    cin>>n;
    for(int i=1; i<=n-1; i++)
    {
        cin>>x>>y;
        graf[x].push_back(y);
        graf[y].push_back(x);
    }
    bfs(1);
    bfs(ult);
    cout<<diam;
    return 0;
}