#include<fstream>
#include<cmath>
using namespace std;
ifstream f("trapez.in");
ofstream g("trapez.out");
int x[101],y[101],n,nr,s[5];
int rez()
{
	int i,j,i1,j1;
	int nr=0;
	for(i=1;i<=n;i++)
		for(j=i+1;j<=n;j++)
			for(i1=1;i1<=n;i1++)
				for(j1=i1+1;j1<=n;j1++)
					if(i!=i1&&j!=j1)
					if(abs((y[j]-y[i])*(x[j1]-x[i1]))==abs((y[j1]-y[i1])*(x[j]-x[i])))
						if(abs(x[j]-x[j1])==abs(x[i]-x[i1]))
							nr+=2;
						else
							nr++;
	return nr;
}
/*int verif()
{	int i;
	int k=0;
	for(i=1;i<=n;i++)
		if(x[i]==1)
			{k++;s[k]=i;}
	if(abs((y[s[2]]-y[s[1]])*(x[s[4]]-x[s[3]]))==abs((y[s[4]]-y[s[3]])*(x[s[2]]-x[s[1]])))
				{		
					{if(abs(x[s[2]]-x[s[4]])==abs(x[s[1]]-x[s[3]]))
							{nr++;return 1;}
					else
					return 1;}
				}
				else return 0;
	
}*/
int main()
{
	int i,s=0;
	f>>n;
	for( i=1;i<=n;i++)
		f>>x[i]>>y[i];
	g<<rez;
	/*i=1;
	while(i)
	{
		x[i]++;
		s++;
		if(x[i]>1){x[i]=0;i--;s--;}
		else
			if(s==4)
				if(verif())nr++;
				else i++;
	}
	g<<nr;*/
	return 0;
	
}