#include<cstdio>
#include<cmath>
#include<map>
#include<algorithm>
#define epsilon 0.0000000000001
using namespace std;
void read(),solve();
map<double,int> M;
int n,i,x[1010],y[1010],precalc[1010],SOL,j,a,b,c,d;
double ung;
int main()
{
	read();
	solve();
	return 0;
}
void read()
{
	freopen("trapez.in","r",stdin);
	freopen("trapez.out","w",stdout);
	scanf("%d",&n);
	for(i=1;i<=n;i++)
	{
		scanf("%d%d",&x[i],&y[i]);
		precalc[i]=precalc[i-1]+i-1;
	}
}
void solve()
{
	for(i=1;i<=n;i++)
		for(j=i+1;j<=n;j++)
		{
			a=x[i];b=y[i];
			c=x[j];d=y[j];
			if(a>c){swap(a,c);swap(b,d);}
			if(a==c&&b>d){swap(a,c);swap(b,d);}
			ung=atan2(double(d-b),double(c-a));
			++M[ung];
		}
	for(map<double,int>::iterator it=M.begin();it!=M.end();it++)SOL+=precalc[it->second];
	printf("%d\n",SOL);
}