/*
TASK: tri
LANG: C++
*/
#include <iostream>
 
using namespace std;



int main()
{
 int n,x,y;
 cin>>n;
int  a[n+1][n+1],b[n+1][n+1],i1,j1,br=0;;
for(int i=0;i<=n;i++)
for(int j=0;j<=n;j++)
{a[i][j]=0;b[n][n];}

 do
 {
  cin>>i1>>j1;if(i1!=0&&j1!=0){
  a[i1][j1]++;a[j1][i1]++;}
 }while(i1!=0&&j1!=0);

 int p=n;
for(int i=1;i<n;i++)
{p--;
 for(int j=1;j<n;j++)if(a[i][j]!=0){
 for(int k=1;k<=p;k++)
 {if(a[i+k][j]==a[i][j]&&a[i][i+k]!=0){br++;}}}
}
cout<<br/2<<"\n";
 
 
 


return 0;
}
