#include <fstream>

using namespace std;

int main ()
{
	ifstream f("trapez.in");
	ofstream g("trapez.out");
	unsigned n, i, j, p, q, k=0;
	long long int x[1000], y[1000];
	bool ok;
	f>>n;
	for (i=0;i<n;i++) f>>x[i]>>y[i];
	for (i=0;i<n;i++)
		for (j=i+1;j<n;j++)
			for (p=j+1;p<n;p++)
				for (q=p+1, ok=0;q<n;q++)
				{
					if (y[p]==y[i]&&y[q]==y[j]&&y[p]!=y[q]&&y[i]!=y[j])
					{	
						k++;
						ok=1;
					}
					else if (x[p]==x[i]&&x[q]==x[j]&&x[p]!=x[i]&&x[q]!=x[j])
						k++;
					if (ok)
						if (x[p]-x[i]==y[p]-y[i]&&x[q]-x[j]==y[q]-y[j])
							k++;
				}
	g<<k;

	return 0;
}