#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#define maxcow 100001
int fir[maxcow],sec[maxcow],tri[maxcow],fou[maxcow];
int xl[maxcow],xr[maxcow],yu[maxcow],yd[maxcow];
int n,pos1,pos2,pos3,pos4,posx1,posx2,posy1,posy2;
int data[maxcow][2];
using namespace std;
double dis(int x1,int y1,int x2,int y2);
void init(int x,int y,int c);
bool success(int x,int y);
double dis(int x1,int y1,int x2,int y2)
{
	double distance;
	distance=sqrt(float((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2)));
    return (distance);
}
bool make(int p,int q);
bool make(int p,int q)
{
	double k;
	k=float(float(data[p][1])/float(data[p][0]));
	if (k*data[q][0]-data[q][1]<0)
		return (0);
		else return(1);
}
void init(int x,int y,int c)
{
	if ((x>0)&&(y>0))
	{
		pos1++;
		fir[pos1]=c;
	}
	if ((x>0)&&(y<0))
	{
		pos4++;
		fou[pos4]=c;
	}
	if ((x<0)&&(y>0))
	{
		pos2++;
		sec[pos2]=c;
	}
	if ((x<0)&&(y<0))
	{
		pos3++;
		tri[pos3]=c;
	}
	if ((x=0)&&(y>0))
	{
		posy1++;
		yu[posy1]=c;
	}if ((x=0)&&(y<0))
	{
		posy2++;
		yd[posy2]=c;
	}
	if ((x>0)&&(y=0))
	{
		posx1++;
		xr[pos1]=c;
	}
	if ((x<0)&&(y=0))
	{
		posx2++;
		xl[posx2]=c;
	}
}
bool success(int x,int y)
{
	double a,b,c;
	a=dis(data[x][0],data[x][1],0,0);
	b=dis(data[y][0],data[y][1],0,0);
	c=dis(data[x][0],data[x][1],data[y][0],data[y][1]);
	if (a*a+b*b-c*c<0)
	{
		return (1);
	}
	else return(0);
}
int main()
{
	int k,a,b,w,pos=0,j,ans=0;
	freopen("tricount.in","r",stdin);
	freopen("tricount.out","w",stdout);
	scanf("%d",&n);
	memset(data,0,sizeof(data));
	memset(fir,0,sizeof(fir));
	memset(sec,0,sizeof(sec));
	memset(tri,0,sizeof(tri));
	memset(fou,0,sizeof(fou));

	for (k=1;k<=n;k++)
	{
		scanf("%d%d",&a,&b);
		pos++;
		data[pos][0]=a;
		data[pos][1]=b;
		init(a,b,pos);
	}
     for (k=1;k<=n;k++)
	 {
		 for (w=k;w<=n;w++)
		 {
			if (k!=w)
			{
				if (success(k,w))
				{
					for (j=w;j<=n;j++)
					{
						if ((j!=k)||(j!=w))
						{	
			            if (make(k,j)==1||make(w,j)==1)  		
						{	
						 ans++;
						}
						}
					}
				}
			}
		 }
	 }
	printf("%d",ans/2);
return 0;	
}