#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];
	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;q<n;q++)
				{
					if (y[i]==y[p]&&y[j]==y[q])
						k++;
					if (x[i]==x[p]&&x[j]==x[q])
						k++;
				}
	g<<k;

	return 0;
}