struct punct { int x, y; };
struct segment { punct p1, p2; };
int sfunc (void * s1, void * s2) {
	segment * ss1=(segment *)s1;
	segment * ss2=(segment *)s2;
	return ( (ss1->x*ss2->y) - (ss1->y*ss2->x) );
};
long Combinanari(long n, long k) {
	if (n<k) return 0;
	else {r=1;
		for (i=k+1; i<=n; i++) r*=i;
		for (i=1; i<=n-k; i++) r/=i;
		return r;
	};
};
int main (void) {
	FILE * fi = fopen("trapez.in","rt");
	FILE * fo = fopen("trapez.out","wt");
	int d;
	fscanf(fi,"%d",&n);
	for (int i=1; i<=n; i++) {
		fscanf("%ld %ld",&p[i].x,&p[i].y);
	};
	for (int i=1; i<n; i++) 
		for (int j=i+1; j<=n; j++) {
			segs++;
			seg[segs].p1=p[i];
			seg[segs].p2=p[j];
		}
	qsort(segs,0,sizeof(segs),sfunc); //!!!
	int pz=0; int off=0;
	long rasp=0;
	while (pz+off<=segs) {
		while (sfunc(&seg[pz],&seg[pz+off])==0) {
			off++;
		};
		off--;
		rasp+=Combinanari(off+1,2);
	};
	fprintf(fo,"%ld\n",rasp);
	fclose(fi); fclose(fo);
};