#include <cstdio>
#include <algorithm>
#include <cmath>
#define eps 0.00000001
#define nmax 1025
using namespace std;
double v[nmax*nmax/2];
int n,m,tot,q;
long long sol;
int x[nmax],y[nmax];

int main()
{
    int i,j;
    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]);
        for (j=i-1;j>=1;j--)
            if (x[i]!=x[j])
                v[++m]=(double)(y[j]-y[i])/(x[j]-x[i]);
            else
                q++;
    }
    sol=q*(q-1)/2;
    sort(v+1,v+m+1);
    for (i=1;i<=m;i=j+1) {
        j=i;
        while (j<=m&&abs(v[j]-v[j+1])<eps)
            j++;
        tot=j-i+1;
        sol+=1LL*(tot*(tot-1))>>1;
    }
    printf("%lld",sol);
    return 0;
}