#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
int n,i,j,x,y,c,g[100005],q[100005],ct,d[100005],mx;
vector <int>v[100005];
queue <int>C;
int main()
{fin>>n;
 for(i=1;i<=n-1;i++)
    {fin>>x>>y;
     v[x].push_back(y);
     v[y].push_back(x);
     g[x]++;
     g[y]++;
    }
 C.push(x);
 q[x]=1;
 while(C.size()>0)
      {c=C.front();
       C.pop();
       q[c]=1;
       for(i=0;i<g[c];i++)
          {if(q[v[c][i]]==0)
              {C.push(v[c][i]);
               q[v[c][i]]=1;
              }
          }
      }
 for(i=1;i<=n;i++)
    q[i]=0;
  x=c;
 C.push(x);
 q[x]=1;
 ct=0;
 d[x]=1;
 while(C.size()>0)
      {c=C.front();
       C.pop();
       q[c]=1;
       for(i=0;i<g[c];i++)
          {if(q[v[c][i]]==0)
              {C.push(v[c][i]);
               d[v[c][i]]=d[c]+1;
               if(d[v[c][i]]>mx)mx=d[v[c][i]];
               q[v[c][i]]=1;
              }
          }
      }
 fout<<mx;
}