#include "stdio.h"

FILE *f, *g;
int a[1001], b[1001], n;
int sum;

int main()
{
	f = fopen("trapez.in", "r");
	g = fopen("trapez.out", "w");

	fscanf(f, "%d", &n);

	for(int i = 1; i <= n; i++)
		fscanf(f, "%d %d", &a[i], &b[i]);

	sum = 0;

	for(int i = 1; i <= n-3; i++)
		for(int j = i+1; j <= n-2; j++)
			for(int k = j+1; k <= n-1; k++)
				for(int l = k+1; l <= n; l++)
				{
					if(a[i] == a[j] && a[k] == a[l] || a[i] == a[k] && a[l] == a[j])
						sum++;
					else if(b[i] == b[j] && b[k] == b[l] || b[i] == b[k] && b[j] == b[l])
						sum++;
					else if((b[j]-b[i])*(a[l]-a[k]) == (b[l]-b[k])*(a[j]-a[i]) || 
						(b[k]-b[i])*(a[l]-a[j]) == (b[l]-b[j])*(a[k]-a[i]))
						sum++;
				}

	fprintf(g, "%d", sum);

	fclose(f);
	fclose(g);

	return 0;
}