#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
using namespace std;

ifstream f("darb.in");
ofstream g("darb.out");

vector <int>arb[100001];
queue <int>q;
int n,v[100001],viz[100001],ultim,ans;

void bfs(int start)
{ for(int j=1;j<=100001;j++)v[j]=0,viz[j]=0;
  q.push(start);
  v[start]=1;
  viz[start]=1;
  int i,vc;
  while(!q.empty())
  {vc=q.front();
   for(i=0;i<arb[vc].size();i++)
    if(viz[arb[vc][i]]==0)
    {q.push(arb[vc][i]);
     v[arb[vc][i]]=v[vc]+1;
     viz[arb[vc][i]]=1;
     ans=v[arb[vc][i]];
     ultim=arb[vc][i];
    }
   q.pop();
  }


}

int main()
{int a,b;
 f>>n;
 for(int i=0;i<n-1;i++)
 {f>>a>>b;
  arb[a].push_back(b);
  arb[b].push_back(a);
 }
 bfs(1);
 bfs(ultim);
 g<<ans;
    return 0;
}