#include <fstream>
using namespace std;

int main(void)
{
	ifstream in;
	ofstream out;

	in.open("triang.in", ios::in);
	out.open("triang.out", ios::out);
	
	int count = 0;
	int n;
	double* numerex;
	double* numerey;
	in >> n;
	numerex = new double[n];
	numerey = new double[n];
	int i;

	for(i=0;i<n;++i)
	{
		in >> numerex[i] >> numerey[i];
	}

	for(i=0;i<n-2;++i)
	{
		for(int j=i+1;j<n-1;++j)
		{
			for(int k=j+1;k<n;++k)
			{
				double l1 = (numerex[i]-numerex[j])*(numerex[i]-numerex[j]) + 
						(numerey[i]-numerey[j])*(numerey[i]-numerey[j]);
				double l2 = (numerex[i]-numerex[k])*(numerex[i]-numerex[k]) + 
						(numerey[i]-numerey[k])*(numerey[i]-numerey[k]);
				double l3 = (numerex[k]-numerex[j])*(numerex[k]-numerex[j]) + 
						(numerey[k]-numerey[j])*(numerey[k]-numerey[j]);
				if(l1 - l2 <= 0.001 && l1-l2>=-0.001 && l2 - l3<=0.001 && l2-l3>=-0.001)
					++count;
			}
		}
	}

	out << count;
	delete[] numerex;
	delete[] numerey;
	in.close();
	out.close();

	return 0;
}