#include<stdio.h>
#define maxn 1001
long x[maxn],y[maxn],n;
long modul(long x1)
{if (x1>0) return x1;
 else return -x1;

 }
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,i3,i4,a,b,c,d;
 NR=0;
 for(i1=1;i1<n;i1++)
  for(i2=i1+1;i2<=n;i2++)
	for(i3=i1+1;i3<n;i3++)
	 for(i4=i3+1;i4<=n;i4++)

		 if(i1!=i3 && i4!=i2 && i1!=i4 && i2!=i3)
		 {if (y[i1]>y[i2]) {a=y[i1]-y[i2]; b=x[i1]-x[i2];}
			 else {a=y[i2]-y[i1]; b=x[i2]-x[i1];}
		  if(y[i4]>y[i3]) {c=y[i4]-y[i3]; d=x[i4]-x[i3];}
			 else {c=y[i3]-y[i4]; d=x[i3]-x[i4];}
		 if(a*d==c*b) NR++;
		 }
 freopen("trapez.out","w",stdout);
 printf("%ld\n",NR);
return 0;}