#include<stdio.h>
#include<math.h>
#define maxn 1001
long x[maxn],y[maxn],n;
int main()
{long i,NR;
 freopen("trapez.in","r",stdin);
 scanf("%ld\n",&n);
 for(i=1;i<=n;i++)
 {scanf("%ld %ld\n",&x[i],&y[i]);}
 long i1,i2,j1,j2,a,b,c,d;
 NR=0;
 for(i1=1;i1<n;i1++)
  for(j1=i1+1;j1<=n;j1++)
	for(i2=i1+1;i2<n;i2++)
	 for(j2=i2+1;j2<=n;j2++)
	  {i++;
		 if(i1!=i2 && j2!=j1 && i1!=j2 && j1!=i2)
		 {a=(y[j1]-y[i1]);
		  c=(x[j2]-x[i2]);
		  b=(x[j1]-x[i1]);
		  d=(y[j2]-y[i2]);
		  if(abs(a*c)==abs(b*d))NR++;}
		 }
 freopen("trapez.out","w",stdout);
 printf("%ld\n",NR);
return 0;}