/*
TASK: tri
LANG: C++
*/
#include<iostream>
using namespace std;
 long hora[600][600];
 long a,b;
 long n,i,j,br=0,br1=0,k,i1,j1;
int main()
{
 // Dano da raboti :)

 cin>>n;


 for(i=1;;i++)
 {
  cin>>a;   cin>>b;
 
  if(a==0 && b==0) break;
 
  else
  {
   hora[a][b]=1;
   hora[b][a]=1;
  }

 }
 
// for(i=1;i<=n;i++){ for(j=1;j<=n;j++) { cout<<hora[i][j]<<" ";}cout<<endl;}system("pause");
 
 
 
 
 for(i=1;i<=n;i++)
 {//glaven for
  for(j=1;j<=n;j++)
  {//for
   
 // NB!! i e 4oveka, a j e poznaiq mu  
 
   if(hora[i][j]==1)
   {//if
    for(j1=1;j1<=n;j1++)
    {//for
    if(hora[j][j1]==1 && hora[i][j1]==1 && i!=j1) {hora[j][j1]=0; hora[i][j1]=0; br++;}
    }//for         
  }//if
 }//for
}// glaven for
    cout<<br<<"\n";

return 0;
}
