#include <fstream>
#define NMAX 100005
#include <vector>
#include <queue>
#define pb push_back
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
vector <int> L[NMAX];
queue <int> q;
int n,diametru,ultim;
int v[NMAX],con[NMAX];
void bfs(int nod);
int main()
{
int i,x,y;
fin>>n;
for (i=1;i<n;i++)
    {
     fin>>x>>y;
     L[x].pb(y);
     L[y].pb(x);
    }
bfs(1);
bfs(ultim);
fout<<diametru<<'\n';
return 0;
}
void bfs(int nod)
{ int x,i,vec;
q.push(nod);
for (i=1;i<=n;i++)
    { v[i]=0;
      con[i]=0;}
v[nod]=1;
con[nod]=1;
while(!q.empty())
    {
     x=q.front();
     q.pop();
     for(i=0;i<L[x].size();i++)
         { vec=L[x][i];
           if(v[vec]==0)
             { q.push(vec);
               v[vec]=1;
               con[vec]=con[x]+1;
               diametru=con[vec];
               ultim=vec; }
        }
    }
}