#include<iostream.h>
#include<fstream.h>
int n,i,j,k,l,a;
struct punct
{unsigned v[10];
}x,y;
int main()
{ifstream f("trapez.in");
 ofstream g("trapez.out");
 f>>n;
 for(i=0;i<n;i++)
 {f>>x.v[i];
  f>>y.v[i];
 }
 for(i=0;i<n-2;i++)
	 for(j=i+1;j<n-1;j++)
		 for(k=j+1;k<n-1;k++)
			 for(l=k+1;l<n;l++)
			{
		    if(y.v[i]-y.v[j]==y.v[k]-y.v[l]) 
			{a++;
			cout<<"("<<x.v[i]<<","<<y.v[i]<<") ("<<x.v[j]<<","<<y.v[j]<<") si ("<<x.v[k]<<","<<y.v[k]<<") ("<<x.v[l]<<","<<y.v[l]<<")"<<endl;}
			}
 g<<a;
 return 0;
}