/*
TASK:man
LANG:C++
*/
#include<iostream.h>
int d[15012][15012];
int main()
{ long m,i,x,y,k,j,br=0;
  int b[15012],c[15012];
  cin>>m;
  for(i=1;i<=m;i++)
  { cin>>x>>y;
    b[i]=x;
    c[i]=y;
  }
  for(i=1;i<=m;i++)
  { if (d[b[i]][c[i]]!=-1)
    { br++;
      for(j=1;j<=i-1;j++)
      { if (b[j]==b[i]) { d[c[j]][c[i]]=-1;d[c[i]][c[j]]=-1;}
	else
	if (b[j]==c[i]) { d[b[i]][c[j]]=-1;d[c[j]][b[i]]=-1;}
	if (c[j]==b[i]) { d[b[j]][c[i]]=-1;d[c[i]][b[j]]=-1;}
	else
	if (c[j]==c[i]) { d[b[j]][b[i]]=-1;d[b[i]][b[j]]=-1;}
      }
    }
  }
  cout<<br<<endl;
return 0;
}
